Many moons ago, in the mid 80's, there I was working Ground at Lajes in the Azores. Glorious summer morning.
Please bear in mind that this happened before the Wall came down.
Now, Lajes ATC was, and still is, manned by mixed nationality ATC's from the USAF and the Portuguese AF.
British Nimrod calls up for clearance. We get it off Santa Maria OAC, and about 20 minutes after that he calls for taxi.
Since he's the only thing moving in the field I'm only kind of glancing at him every now and again.
Almost in slow motion the guy working Flight Data (an American) gets up, reaches for the binoculars and goes "What the F
k ...???"
You see, the Nimrod has a kind of hatch on top of the fuselage, which in this occasion was open.
Out of it was one of the crewmembers happily waving a HUGE SOVIET UNION FLAG.
Out of a British Nimrod.
In a Nato base.
Needless to say, the Americans went beserk.
Crash phone activated for a possible hijack, military police cars full of armed boys swarming all over the aircraft, fire engines blocking the runway.
In the mean time, trying to control my tears of laughter at both the british joke and the look on the yanks faces, I managed to tell the, by this time having serious second thoughts, aircraft commander to shut down is engines, open his doors and prepare to be borded.
Heard afterwards that he had a lot to explain to his Squadron Leader.
Cheers