Board Thread:General Discussion/@comment-24280747-20131212040815/@comment-24280747-20140107202551

You have to play around a lot. Try looking for these ones (they may be only for me but I think they're universal); in AC6, during Mission 10 there is a Strigon plane and in Mission 11 there is an F15E which are glitched or supposed to imply skilled pilots. After damaging the planes until they are almost shot down, the planes become un-destroyable and you will not be able to shoot them down until later on in the mission, after destroying other enemy planes or using your wingman/allied attack.