I noticed in Nuts and one of the BoB scenarios that your wingmen wander around when they have been hit. They just fly straight because of damage. If you play Nuts on Arcade and you don't know what to kill (which is a common problem) you end up shooting everything on the ground hoping for the best. I repeatedly shot up ground targets and all of a sudden Mission Complete. I didn't do it, so eventually it appears they will get it done unless time runs out (simulation). I also noticed a lot of 109s in BoB scenarios smoking. Just watching them I discovered it was the bombers (Brirish bombers) hitting them, not your wingmates. But the wingmen DID finish them off. At times they help, and at times they don't.