Imho fighters are pretty effective in early game, later they lost because the are not affected by minituarisation, but beam weapons on ships - what fighting with them - are...
...other thing is that in original MOO2, the space 30 for interceptors is a little lot... best balanced is imho Mictian mod, where they cost 20 space, what looks be ~ optimal... at least for me. But even for 30 they can have good value in mid-game.
They are basically like missiles, but with some differences and advantages. Like missiles, best are they when are used "en masse", where they overvhelming the enemy PD. Like missiles, it is not good launch them on long range - if the enemy is not desorganised and he has has enought regular beam weapons, they will have losses and efficiency of thier attack will be limited.
Like other "smart weapons", do not combine them on thier carriers with beam weaponry - it is wasting with the space, equipment and even experience of the crew (im using commonly newly produced ships, with unexperienced crews - which are not efficient in beam combat - like fighter carriers)... but you can combine them with bombs, pulsars, missiles or anti-missile rockets on the ship.
Most usefull from fighters are imho assault schutles and interceptors. Schutles because they attack with different way - the enemy is here not defendet with shields and armour like opposite other weapons - and some opponents are very weak when comes on hand to thand combat with marines. Interceptors are interesting because they cost less, and are very versatile.
Opposite missiles, interceptors heve such like advantages:
- they do not need so many technologies to be efficient. With discovered only Fighter Bays (80 RP) and Fusion Beam (150 RP), you have very efficient ship weapon.
- they attacking target allways from the side, where he has weakest shields
- they are not affected with anti-missile rockets, they are more resisant oposite to consequential explosions, they can be allways fired all in one salvo without Fast missile racks, they have even thier build-in Dautness Guidance System for free
, they are unaffected with ECM and if they survives thier first flight, they can be reused and send to other attack (not common, but especially in big scale battle, you will have some part of them reused).
- they are more versatile - you can attack with them ships, other fighters, missiles. They are pretty effective like "one shot PD", even on long range, in game phase, where you do have not efficient beam weaponry.
- they can attack up to 4 different targets on one launch. You can not control them in flight, but they will attack your first assignated target and then, after his destruction, they will simply do what they can do. You can send them on aprodaching missiles, they will destroy them and then they will continue with other targets.
- they take thier space on ship, but after while, they are alot cheaper in terms of manufacturing costs. Commonly you are more affected by the command points, but in artritidion warfare, in emergency situations, when you playng for Warlord, or even you have strenght economy to take the costs, small Destroyer/Cruiser sized carriers can be manufacture pretty fast.
- they are automatically modernised on ships when are new technologies discovered - when you lead campagin on frontiers or on enemy territory, you often do not have time to go back in shipyards to modernise your weapons on whole fleet. But when you will discover new armour or better point defence moddable beam weapon, all your fighters on your ships will be automatically equiped with them.
One "tactic" what has worked pretty efficient for me: if is the long-range heavy mount beam weaponry not the main thread for your ships, do not launch your interceptors first. Stay in positions, click on the wait button. If your carriers can survive the first enemy long-range beam weaponry salvo, you can react on the enemy moves and send interceptors opposite to incomming missiles - concentrate them on the main threads, and they will kill the missiles on route and do not waste thier time with pursue. When they will destroy the assignated target, they will immediately continue with the attack on closest enemy ships. With this action you will get three benefits: reduce the enemy missile thread, strike on the closest ships and employ the enemy beam weapons with defensive fire on fighting interceptors. Not bad for the costs.