As I understand it, this is a difference in NFHS and NCAA rules. In NFHS, the runner gets the benefit of the goal line extended only if he is touching inbounds. If he is airborne, it doesn't matter how he got that way, he has to get the ball inside the pylon.
In the NCAA, the runner gets the benefit of the goal line extended if he is inbounds or was KNOCKED airborne. The only time he does get it is if he went airborne on his own.