I agree that this could be made an option, if possible, but I'd choose "HA cannot die"

I've always liked how OFF and WOFF tried to maintain their close-to-historical roots as much as possible. So, maybe other options like:

1) Newspaper report that a HA was shot down but managed to survive the crash to live to fight another day. He may need a few days of recovery time, but will bounce back (cats may have 9 lives, but HA can have 10 )

2) Extra ribbon or recognition (or other reward) for shooting down an ace, who happened to survive the crash.

3) Reduce the frequency of missions that an HA can fly to lessen the odds of encounters. Side effect - May offest the historical accuracy of the actual number of mission that he flew during the war.

EDIT: 4) Imagine that the HA who was shot down...... survived the crash