There used to be an old RAF joke that I can't quite remember now but part of it was 'How do you know if there's a Harrier pilot at a party? His wife will tell you.'
Thing,
The slightly different one which I know from my Harrier friend is "how do you know theres a Harrier Pilot in the room?" because he'll tell you! ...Now I believe its Typhoon pilots...
ps..like the driving down the centre line of the road one...I ahve to think twice sometimes, especially after a lesson in the circuit!