I would prefer it if it could sustain damage, but surround it with an impenetrable wall of AAA, Barrage balloons and fighter screen.
Also if it was damaged, the demeanour of the defending AI forces should become extremely agitated and aggressive, and be solely focused on destroying the offending aircraft.
Also the crew upon return to their aerodrome should then be arrested, court-martialled, stripped of rank and summarily shot for disobeying the strict orders not to attack the palace.
Well that's what I'ld do!
