[Jurassic Referee]

As long as the pivot foot never came back down, it was legal. From your description though, I'd be hard-pressed to believe that it didn't on this play. It's hard as hell...to the point of being almost impossible imo... to stop in mid-drive and balance yourself on a non-pivot foot. The usual scenario in a drive is jumping off the non-pivot foot and shooting before the pivot foot again lands. From your description, it sounds like the shooter let his pivot foot land to let the defender fly by.