I think Vietnam may be the exception, at least for helos. Though I also wonder if those numbers might be skewed because I think they called any bird lost in Injun Territory a combat loss. Plus we were basically utilizing helos like they were disposable.
Combat loss =/= Shootdown.
By the way the doctrinal understanding went/goes, a combat loss is a non training event which the condition and environment dictates. So if you’re doing a dust landing to perform a medevac and the aircraft rolls over, it still counts even though no enemy could have been part of the equation.
Conversely we have had non combat losses in combat zones such as an aircraft that suffered damage conducting roll on landings for progression and F’ing it away.