American Football NCAA Rule 2-27-15

a. Out of Bounds
1. A player is out of bounds when any part of their body touches anything other than another player or a game official on or outside a boundary line.
2. An out-of-bounds player who becomes airborne remains out of bounds until they touch the ground inbounds without simultaneously being out of bounds.
b. In Bounds
1. An inbounds player is a player who is not out of bounds.
2. An inbounds player who becomes airborne remains inbounds until they are out of bounds.