Originally Posted by Jetjok

...One day, high above Arizona, we were monitoring the radio traffic of all the mortal airplanes below us. First, a Cessna pilot asked the air traffic controllers to check his ground speed. "Ninety knots," ATC replied. A twin Bonanza soon made the same request. "One-twenty on the ground," was the reply. To our surprise, a navy F-18 came over the radio with a ground speed check. I knew exactly what he was doing. Of course, he had a ground speed indicator in his cockpit, but he wanted to let all the bug-smashers in the valley know what real speed was "Dusty 52, we show you at 620 on the ground," ATC responded.

The situation was too ripe. I heard the click of Walter's mike button in the rear seat. In his most innocent voice, Walter startled the controller by asking for a ground speed check from 81,000 feet, clearly above controlled airspace. In a cool, professional voice, the controller replied, "Aspen 20, I show you at 1,982 knots on the ground." We did not hear another transmission on that frequency all the way to the coast....