Fighters aren't even a realistic evolution of current naval warfare. It'll all be drones as soon as is practical, and when someone works out an effective laser anti-aircraft system, it'll be back to battleships again.

However, the more I think about it, you’d want to take out your enemy’s missile launchers,

Warfare in space is likely to involve excessive amounts of energy, one way or another. Kinetic projectiles with relative speeds of tens of kilometres per second. Nukes. Massive laser cannon. You don't "take out their launchers", you wreck their ships.

If you meant "take out their missiles at a distance" you might be closer to the mark, but that's a job for high-speed, fast-reacting expendable interceptor missiles, not fighters.

both sides would develop AA technology for their ships, or counter with fighters

If the principle weapons of the warships are missiles, then the principle defense will be counter-missiles, point defense projectile weapons and lasers. You can already see the convergence of missile and aircraft defense in modern missiles like the Aster. Anti-ship missiles will be travelling faster than a fighter (no need to be delicate with the meat, or carry unnecessary weight) and be able to manoever harder, and any countermeasures capable of taking out one of those missiles will easily be able to take out a fighter.

would they be most likely to stay in capital ships and just try to shoot down the missiles?

Yep. There are multiple problems with fighters, you see.

Firstly, meat is delicate. You need life support (heating, cooling and air), radiation protection and limited acceleration forces or the pilot becomes so much pâté and your expensive fighter ends up as the tin. Computers think and react faster than people. Maybe you could just upload your pilot, of course, so they might better compete with AI systems?

Secondly, the rocket equation is punishing. Your missiles just need to accelerate up to some speed $v$, jink about a bit as they enter range of enemy point defense or interceptor missiles, then go bang. You fighters, at a bare minimum, need to speed to up $v$, then in order to get back home they need to slow down to a relative stop (a change of speed equivalent of $v$) then accelerate back up to $v$ and finally slow back down to a halt at their mothership. That means they need a total velocity change, or delta-V of $Delta_v = 4v$. According to the rocket equation, your $Delta_v$ is proportional to $ln(m_0/m_f)$, where $m_0$ is your empty mass and $m_f$ is your fully fuelled mass. To increase your $Delta_v$ by a factor of 4, you mass ratio needs to increase by a factor of $e^4$ which means you need fifty four times as much fuel as the missile. What a huge waste! A missile that big could travel 4 times as fast, or manoever for much longer, or carry a massively larger warhead, or multiple warheads. Maybe you could have your fighters run dry at the target, assume you'll be victorious and come in to pick them up with the carrier, but that's a risky strategy and even then they'll need nearly 3 times as much fuel as a missile would.

I’d say they’d probably want to be capturing enemy ships if possible

Enemy point defenses might have ranges of thousands of kilometres. You want to reach them at more or less zero-speed in order to board them. Even if you brake super hard, at the limits of human endurance, you're still in the danger zone for a relatively long time and you'll be toast. You could nuke em until the point defenses stop, but at that point they're probably nothing but a rapidly expanding and cooling cloud of gas and dust.

You don't board a ship capable of defending itself. Even civilian ships might be tricky. Only people who surrender can be boarded, and then you can do it with any kind of shuttle. No need for fancy boarding craft.

This was a comment at first but I've decided to turn it into a full-blown answer.

You suggested evolutionary path is as follows:

• Space warfare consists of two fleets of ships lobbing missiles at each other


• The fleets would develop and deploy bombers to fly in close and take out the other fleet's missile launchers


• The fleets would in turn develop fighters to shoot down the bombers before they can destroy the launchers

A simpler and much more logical progression would be the following:

• Space warfare consists of two fleets of ships lobbing missiles at each other


• The fleets would adapt their missiles so they can be steered mid-flight, allowing them to dodge counter-measures and strike specific parts of an opposing ship (such as the missile launchers)

Compared to developing whole new fleets of bombers and fighters, simply upgrading to guided missiles would be far more cost-effective, take advantage of systems that the ships already have instead of requiring new hangars/carriers to be built to accommodate them, and would not require human pilots that would be at great risk of getting blown up. As you mention that your mafia fleet would want to capture ships where possible, they can also use guided missiles to hit things like engines or shield generators, crippling a ship without destroying it entirely.

No

With all due respect to any answer that suggests yes, nobody's thinking about what it takes to move mass around in space. Even when orbiting a planet, you really don't have the benefit of gravity to reduce your fuel costs — and that assumes you're moving slow enough for two ships to engage with piloted (in any form) fighters.

The Ugly Details

Let's ignore relativistic combat for now and stick with simple, run-of-the-mill awe-inspiring sublight. Let's say our capital ships are booking along at a creeping 1,500,000 kph (that's the Earth to the Moon in 15 minutes).

If the two capital ships happen to approach one another at a very acute angle, they can sidle up to one another (broadsides) and thump it out with fighters because the fighters are moving at the same relative speed (along the same 1.5 Mkph vector) as the capital ships.

But if those big bugaboos come at one another at obtuse angles, it would not only be a pain in the neck to take the time (and fuel) to adjust course to come broadside, it would be a defensive faux pas. Unfortunately, any fighters launched now get one shot at the enemy capital ship (and fighters) as they go bookin' past them at a minimum relative speed of 1.5 Mkph (and more likely 2.25 Mkph-ish, depending on the angle).

And heaven help the now useless fighters if the two ships approach one another head-on. Fighters now get just one shot as they pass the enemy at a relative speed of 3 Mkph.

See the problem? Even a fighter can't simply turn on a dime. Spinning around to take a second shot would flatten the pilot against the hull of the ship and turn him into a thin strawberry paste that might, maybe, be contained to his environmental suit.

And can you see why I could ignore relativistic speeds? They just make everything worse.

And speed has another consequence...

Timing. Those pilots get one shot, but I very much doubt any human could time the shot and succeed without simple, blatant luck. Maybe, maybe, that one shot can occur within the window of a single second. Now you go get on your bicycle and try to fire a water pistol successfully with a window of a single second. Yeah... Make sure you post the video on YouTube. :-)

And the faster the capital ships get, the worse this all gets. Time, velocity, and mass are not on the side of fighters in space combat.

So where would they be useful?

Space stations, which in the grand scheme of celestial mechanical things are the equivalent of fixed fortifications.¹ Since they're philosophically not moving, you can launch fighters from them. Why is this at all practical? Because attacking ships moving at speed have but one shot, then they're taking the proverbial month to U-turn (or slingshot around the planet, which is the Star Trek version of a U-turn).² Their option is to slow down to engage the space station, making fighters viable.

But, the short answer is still no.

However, when all is said and done, I simply don't see fighters in the future of space combat. For every condition someone can come up with where they might seem plausible, I'm convinced I can point out some deficiency that would make any other tactic more plausible (especially economically plausible).

_{¹ "Fixed fortifications are a monument to the stupidity of man." — George S. Patton. Space stations are almost as useless as fighters when it comes to combat in space. They simply can't move fast enough to defend against bombers moving at any speed, but the faster those bombers go, the more successful their bombing run. Time, velocity, and mass. Yes, you could build a plethora of space stations — but you might as well build ships and ignore the stations.}

_{² I've seen The Wrath of Khan like, a million times. So by force of habit I'm certain this statement is absolutely true. :-)}

The difference between a fighter and a missile/drone is the missile/drone doesn't have to worry about the squishy human and their life support system taking up mass and volume and limiting manoeuvring to magnitudes humans can survive. That allows the drone to be more manoeuvrable and smaller than an equivalent fighter or bomber attempting to do the same mission.

Not in the way that you'd think, but you still don't want a single point of weakness (capital ship)

Space is treacherous, and in most cases a single hit is probably enough to "kill" your ship (especially with any weapon designed to do so). So, if you're engaging in space combat it doesn't make sense to put all of your people on a single ship. The more you are spread out the harder it will be to kill a significant number of your forces. The enemy will need at least 1 missile per ship assuming 100% accuracy and 100% kill rate, so the more ships you have (regardless of size) the more protected you're forces will be.

It really doesn't make any sense to have any ship be a "fighter" as in star wars, as has been stated in other answers making unmanned guided missiles is far superior. The missile technology would probably be improved greatly and there might be a lot of innovative and cool types adapted for certain enemies or purposes: AI guided, cluster/fragmenting, thermal, explosive, von neumann etc. just to name a few.

Perhaps the ideal is to have the capital ships be modular so that they can be together most of the time, but then break up into hundreds of small autonomous ships (hopefully with their own missiles) when there is a battle. Additionally there should be a number of unmanned sacrificial ships who's job it would be to get in the path of the missiles (they should look similar to all the others but have no people on board and maybe only one intercept missile).

In Earth naval history the earliest tactics were boarding ships and/or ramming ships. Ships basically had to come into contact with other ships to fight them.

The invention of shipboard cannons changed that. Ships could now attack and damage each other at distances of hundreds or thousands of feet. Standard naval tactics were for two fleets to sail parallel to each other and shoot across the distance, though there were also battles with confused melees and ships getting close to their enemies.

As weapons and armor technology rapidly developed during the 19th and early twentieth centuries the ranges of shipboard artillery vastly increased. Battle fleets began to be separated by greater and greater distances when they fought, until the enemy fleets might be on the horizon or beyond it when firing.

During some 20th century sea battles some ships with inferior guns exploded after being hit by shells fired from outside of the range of their own guns, and sank with the loss of 99 percent of their crews or even with no survivors at all. And the same thing would happen to space warships that try to fight space warships that have longer range weapons.

In the late 20th century this trend continued with the development of warships armed with guided missiles that could hit targets on land or other fleets hundreds of miles away. As well as submarines armed with missiles with atomic warheads to hit targets hundreds or thousands of miles away.

And in space warfare the trend is likely to continue with space fleets firing missiles or ray guns at enemies separated by distances of tens or hundreds of thousands, even millions, of miles.

If one fleet has weapons which are effective at a much greater range than their enemy has, they can stay within the range of their weapons but outside of the range of the enemy's weapons, and destroy the enemy fleet without suffering any damage to their own fleet.

But if the fleet with shorter range weapons is faster than the fleet with longer range weapons, the fleet with shorter range weapons can use its greater speed to close the distance to the fleet with longer range weapons and attack it, or else retreat outside the range of the fleet the fleet with longer range weapons.

So imagine an inferior fleet retreating from a superior fleet to avoid destruction. What happens when the ships in the retreating fleet have different speeds? That would be a case of "the devil take the hindmost", wouldn't it? The slower ships would be destroyed or have to surrender first, while the faster ships would be destroyed h or have to surrender later, or possibly escape from the pursuing fleet if faster than it.

Maybe the ships would stick together. In that case the retreating fleet would be limited to the speed of the slowest ships. If the slowest retreating ships were slower than than the pursuing ships, the pursuing ships would catch up to the retreating fleet and totally destroy it.

So that suggests two possible strategies:

1) Make your space battleships as fast as possible and thus add faster ships to the fleet as soon as they are built, even though it means that your fleet will have ships of varying speeds.

or:

2) Only use fleets with ships of identical speeds, even if it means totally retiring all ships of older designs when faster ships are developed and thus having fewer total ships.

Decisions, decisions.

Note that in a space opera conflict between two space traveling species which have just met, the two sides might be totally ignorant of the technological capabilities of their opponents. The crew of a space fleet might not know whether they are centuries more advanced than their opponents and thus will destroy them effortlessly, or are millions of years behind their opponents and thus will be wiped out without doing any damage to the enemy.

Note that with normal space travel space ships will not have speeds so much as acceleration and deceleration capacities. Of course if some sort of FTL space drive is invented it might have either acceleration or speed depending on various factors.

The need for superior speed or acceleration than the enemy will tend to favor larger and larger space warships. A larger spaceship can have larger and more powerful engines and fuel supply relative to its size and mass than a smaller spaceship, while still having as much space left over for weapons as the smaller spaceship and being just as powerful and destructive as the smaller spaceship.

The need for more powerful and longer range weapons than the enemy will tend to favor larger and larger space warships. A larger spaceship can have larger and more powerful weapons relative to its size and mass than a smaller spaceship, while still having as much space left over for powerful engines and fuel supply as the smaller spaceship and being just as fast as the smaller spaceship.

So I imagine that in an interstellar space opera context space battles will involve fleets of space battleships instead of space cruisers or space destroyers or space pt boats.

What about naval aviation? In the mid 20th century aircraft carriers with small fighter and bomber planes ruled the seas.

Surface ships travel at the intersection between the medium of water and the medium of air. The dense water medium provides a lot of resistance to their hulls and limits their speeds.

Small carrier based aircraft travel in the medium of air, which has much less density than water and so offers a lot less resistance to the movement of airplanes. So a tiny aircraft carrier plane can have a tiny engine compared to a surface ship and still travel much faster than the surface ship because of the much lesser resistance of the air.

So imagine that there are two mediums in outer space, and that they met at a plane surface. Suppose that the equivalent of space battleships travel at the interface between one medium and the other. Suppose that the equivalent of space carrier aircraft travel only in one of those mediums, the medium that is much less dense and offers far less resistance to them. Therefore a tiny space fighter craft with a tiny engine could travel much faster and be much more maneuverable than a space battleship slowed down by partially travelling in the denser medium that offers far more resistance.

In that situation, tiny space fighter craft would be very useful in space battles and might be the dominant force in them, as carrier based aircraft were the dominant force in World War Two naval battles.

But of course interplanetary and interstellar space is a hard vacuum, with a very, very, very, very thin scattering of energy and matter. Outer space has no medium to offer resistance to vehicles, let alone two very different mediums with a plane surface between them.

So small fighter vehicles should have very little use in space war.

The AEGIS automated weapons system would work even better in space.

Big American ships are protected by AEGIS, an automated weapons system that shoots down incoming missiles and drones with a combination of missile types and automated machine guns. The phalanx automated machine guns are especially awesome and terrifying.

A system just like this would work even better in space. Radar can see immense distances. You do not have the horizon to hide behind. The guns especially would work well because a bullet put in motion would keep going indefinitely, not slowing from air resistance and dropping from gravity. If you can spot an incoming missile thousands of km away and you have a robot machine gun at the ready, the missile has no chance.

Needless to say a dude in a ship has less chance. Unless the dude is piloting an enormous cargo ship, in which case he has a reasonable chance of ramming a big American ship in the middle of the night.

The only feasible weapons in a duel between two capital ships in space are those which cannot be seen coming: lasers which move at light speed, and particle beams which move at a significant fraction of light speed. Pretty much anything else you will see coming in time to intercept.

If light speed weaponry is blocked somehow, then what? Capital ships would fire back and forth, striving to develop faster projectiles and faster countermeasures. Greater proximity means less time for your opponent's defense. Capital ships might get closer to one another in hopes of getting a shot through. Eventually the ships are practically next to each other, firing and blocking at immense rates.

If you can't throw the ball, run the ball. The ship itself is too big to block. The attacking ship would come alongside its opponent and send over boarding parties.

I think fighters do make some sense, on the condition that they're not manned. Look at how the rocket equation works. Almost always, high thrust engines get poor fuel efficiency. They accelerate quicker, but get worse top speeds and/or ranges. But your missiles need to be able to accelerate quickly to evade enemy point defenses. If you use fighters instead of launching missiles directly from your capital ships, you can get the best of both worlds. The fighters relatively slowly carry the missiles right up to the edge of your enemy's point defense bubble, then they launch their fast missiles at their targets, and go back to the carrier to reload and do it all again. See, you get long range thanks to the fighters, and you get extremely agile missiles because they have the fuel budget to spare on high thrust, low efficiency engines.

I don't think so. Starfighters require its own fuel, a pilot, life support... It's quite expensive. Fly a drone. A solar powered drone. It's cheap, and safe.

Or shoot a massive missile from, let'say, Earth to Mars. Maybe you don't even need an expensive fleet. Or use terrorism to win wars.

Due to the rocket equation, no, Star Wars-style fighters would be impractical. This is because the starfighters would have a truly horrendous mile-per-gallon rating.

However, I suggest that you take a look at the Star Trek style. These are essentially just little starships, which act similarly to the Torpedo Boats that the U.S. used during WWII.