You are looking a nearby mate HOing a nikki, your mate is disintegrated and the nikki looses a wing and fall near you. Surprise the kill is yours.
You are taking off from when you see a P38 trying to deack your field. The ack fried him and surprise, the kill is yours.
You are in a PT boat near your CV heading the coast and then you see a LANC falling near you, surprise, the kill is again yours.
You are in a M16 near an enemy field and a B17 failed to climb a nearby mountaing, surprise again, the kill is yours.
Too many kills without a single shot. IMO, kills should be awarded only if you pinged the target, else you are only a spectator of an accident. IMO, real maneouver kills are very rare while the other cases are the typical ones.
There are tons of deaths by the acks of fields or CV group that are given to the players. What about having the ack as a present enemy, so you get the message "you have killed by the ack". In the other hand, when you are killed by the ack and no enemy is present, the kill is not added to your plane count of deaths.