I've noticed that when you have an ability or structure that provides free interceptors defending a planet, that the AI gets quite caught up on these.
They'll happily attack them, and then next turn repeat... and repeat... and repeat... because the interceptors just regenerate. They'll ignore shipyards and starbases/etc. so it basically makes my empire a giant sand-trap for their fleets.
It's quite handy when being attacked by peacekeepers as my empire merrily continues building itself and fleets, while the dangerous space robots just mindlessly destroy my free and sacrificial pilots.
Just figured I'd throw this out there. The AI could use a tweak to just ignore such ships. I definitely recommend that fighters/drones for these abilities and carriers become their own hull type... as it would make it easier to program the AI in this way and balance the designs and qualities of carriers/etc.