seafire6b,
I reckon Trenchard had the right of it. The object of the exercise must be to render the pilot a non-combatant because (from my Post p.116 #2317 on "Gaining a RAF Pilot's brevet in WWII"):
...in order to expand an air force quickly, aircraft production is a secondary matter. Once you have got the assembly lines going, you can turn out aircraft like family cars. But no air force then or since has been able to train a man from scratch to operational pilot in less than a year. That is your bottleneck...
Time is the currency of war....
Another good reason for not shooting at a parachutist - you may need all the ammo you've got for yourself in the next ten seconds (for dealing with the Zero [or whatever] that's just appeared from nowhere and is having a go at you !)
In many cases an aircraft described as the "Mitsuibishi A6M Zero" (well known) is actually an "Oscar" (much less well known) Nakajima Ki-43 (the bane of our lives in Burma). ''
...the Ki-43 shot down more Allied aircraft than any other Japanese fighter and almost all the JAAF's aces achieved most of their kills in it...
[Wiki]. (Not unlike the Spitfire/Hurricane story in the BoB).
Not easy to tell apart in a scrimmage:
Mitsubishi A6M3 Zero Model 22 (NX712Z)
Nakajima Ki-43-IIa
and with much the same performance.
Danny42C.