I was playing last night with Wonder/Diplomatic/Science victory disabled (serious difficulty) so that the game would move further into the tech tree.

One of the battle reports showed that the AI's best weapon were fighters (I had no point defense). So late game, they probably are effective.



For invasion, a fleet of 10 or more destroyers (2 slots for heavy troops) with Siderite healing module can literally invade every turn, with immediate and free replenishment of losses. (Each modules heals 0.1 on fleet) Invading this way only destroys population, leaving the planet intact (but on strike). Again, this is on serious difficulty; I am not sure about impossible or endless difficulty.



Also, the power modules on the right side of the weapon tree, affect the entire fleet, making a large fleet of small ships extremely powerful.



Anyway, I add the battle version of fighters and bombers late game (which take 2 slots). This leaves 1 slot on defenders, and 1 slot on Battleships if you want to add some point defense.



Remember, this is late game with many of the techs researched in all 4 directions, which is why I disabled Science victory, so I could play with the advanced modules and weapons.

Well, the only thing that stops Bombers are: Fighters, PointDefense, and Armor. So they are very good for inflicting damage to the enemy without regard to their defenses.



The first tier can't do much, though. The second tier of Fighters and Bombers that you research can do some damage, though.



Plus you need them to drop bombs.

Well, they look cool, and are unlikely to be countered by the AI (I select the battle version.).

They are very expensive in terms of tonnage, so probably of limited use.

They don't show up in the battle report, so I am not sure of the actual damage done.



However, sometimes the basic weapons have very low efficiency because of the enemy defenses, so perhaps some of the fighters and bombers are useful.



For invasion, I strictly use elite troops or heavy elite troops - no mechs.