Steal a Harrier / Hawk
This was apparently a real threat, made by some ex-R.A.F pilot who had a major chip on his shoulder.
Since there was only one airfield he could mean, it didn't help his chances that he publicised his intentions !
We were instructed by a certain famous C.T.P / Airfield Manager to always leave a vehicle parked in front of flight line aircraft, resist any attempt if possible but if faced with weapons, let him go & the R.A.F. would deal with it...
Of course the worry is the people underneath.