Hang time is how long the football remains airborne after it has been kicked either after a punt or a kickoff.
Kickoffs are generally more focused on distance, and receive slightly less hangtime than punts. Hangtime is also not recorded as a primary stat during kickoffs as it is with punts, despite it being a valuable tool. Kickoffs that remain in the air for longer allow for the coverage teams to get down the field and tackle the return man before they get too far. A good kickoff hangtime in the NFL is above an average of 4.4 seconds, with the leaders being around 4.7 seconds. College and other football league players average slightly less, but still above four seconds.
When discussing hang time, punts are the usual focus. Punters are judged and chosen partly because of how long they can keep the ball in the air. A line drive 60 yard punt that is returned for 25 yards is much less sought out than a punter that can loft a ball 45 yards resulting in no return. Punters can reach around 5.5 seconds in hang time and the end of season, and leaders are generally around 4.8 seconds.
Launch angle is extremely important in generating as much hang time as possible. A lower launch angle means a line drive, or a kick that will go far and not high. A higher launch angle will not travel as far, but will remain in the air for longer. In deciding between punting the ball far and generating hang time, it is important to find a medium.
One strategy punters use to balance the two is to have their distance be less than 10 times their hang time. For example, a punt that goes 50 yards should have a hang time exceeding 5 seconds.