Unless you are Shuttle pilot I guess this one takes the prize.
"In his book 'Sled Driver', SR-71 Blackbird pilot Brian Shul writes:
I'll always remember a certain radio exchange that occurred one day as
Walt (his back-seater) and I were screaming across Southern California,
13 miles high. We were monitoring various radio transmissions from other
aircraft as we entered Los Angeles airspace. Though they didn't really
control us, they did monitor our movement across their scope. I heard a
Cessna ask for a readout of its groundspeed.
'90 knots' Center replied.
Moments later, a Twin Beech required the same.
'120 knots' Center answered.
We weren't the only ones proud of our groundspeed that day. Almost
instantly an F/A 18 smugly transmitted:
'Ah, Center, Dusty 52 requests groundspeed readout'.
There was a slight pause, then the response:
'525 knots on the ground, Dusty'.
Another silent pause. As I was thinking to myself how ripe a situation this
was, I heard a familiar click of a radio transmission coming from my
back-seater. It was at that precise moment I realised Walt and I had become
a real crew, for we were both thinking in unison.
'Center, Aspen 20, you got a ground speed readout for us?'
There was a longer than normal pause:
'Aspen, I show 1742 knots'.
No further enquiries were heard on that frequency."