It comes from the name of the ex Formula One driver Mark Webber. He was "
flying" with the car many times.
He did wheelies, and sometimes he really took off with the car after a crash... and before an other crash, like in Valencia, in
2010.
In his pre-
F1 years, he was driving at the Le
Mans 24H and guess what? He was flying with the car. That was a horrifying crash, but he survived without damage, he simply walked away.
So when someone "flies" with his car, he is simply webbering.