This happened a few years ago at Maastricht UAC shortly after CPDLC (Controller-Pilot Data Link Connection) had been introduced. Not many airlines were Data Link equipped so we reckoned this new cockpit feature would be tempting to play with.
A United Airlines flight from Frankfurt to the States entered our airspace, still climbing to FL320. Suddenly this particular flight requests FL380 via Data Link, much to our surprise as it is quite a high cruising level to start with for a long haul flight. So the radar controller asks him via voice transmission:
Maastricht: "UAL123, we've just received your request via CPDLC... uhm... confirm you are actually looking for FL380? Or are you just trying out the Data Link system?"
UAL123 (without missing a beat): "Sir if I'd be testing the Data Link system I would ask for a tall Scandinavian blonde, don't you think?"
Maastricht (with an amused voice and laughter in the background): "Haha, I guess!"
After a brief pauze a deep male Scandinavian voice came on: "What can I do for you?"
UAL123: "Uhm... uhm... well, it's not for me - it's for the co-pilot..."
At Maastricht we were on the floor laughing!
