More seriously I have read a comment from a WW2 fighter pilot (I wish I could remember the reference) that he couldn't fault German pilots who fired on British aircrew as they descended by parachute over the UK, as they could be back up flying within hours and thus could be considered fair game.
The pilot's name was Hugh Dowding and when he said it to Churchill, Winston was gobsmacked. Goring did suggest such an action as policy to his Fighter wing leaders during the Battle of Britain, and the Fighter commanders refused point blank to even think of doing it.