also: jet motion · jet sweep · fly motion · fly sweep
Jet motion is a receiver running flat across the formation at full speed. Jet sweep is the play where he gets the ball. Every jet sweep uses jet motion and most jet motion is not a jet sweep, which is the confusion.
2 meanings, all below. Jump to the one you heard.
A receiver or wingback runs flat across the formation at full speed, timed so that he is passing near the quarterback at the moment of the snap rather than arriving afterward. The speed and the timing are the definition; a player jogging across is doing something else.
What it does to a defense is force an immediate horizontal response from players who also have run responsibility inside. A defender who chases him has left a gap, and a defender who does not has let a fast player run free to the edge.
fly motionjet sweep, orbit motion, return motionThe play where the jet man gets the ball, taking a handoff or short toss as he crosses and continuing to the edge. It is one of the fastest-developing runs in football because the carrier is already at full speed when he receives it.
Holding the two terms together matters because the motion is the more important half. Most offenses that use jet motion run the sweep a small fraction of the time and use the motion constantly, precisely because the threat of the sweep is what moves defenders on every other play. A coach who installs the play without understanding that has bought the least valuable part.
fly sweepjet motion, toss and pitch, speed optionFly and jet are used interchangeably by most coaches for both the motion and the sweep. Where a staff distinguishes them, the usual split is aiming point and depth, with fly being flatter or deeper depending on who you ask, and there is no settled standard to appeal to.
This is where the Wing-T's dated distinction lives. Jet appears in one of four sources describing the classic Wing-T and in none of the three describing the historical offense, but it is near-universal in modern youth football. Both facts are true: jet is a later addition to the family rather than part of its classic base, and a coach who runs Wing-T today almost certainly runs it.