Yeah, Carol. If the wheels don't touch it's called a "low pass." And typically both low-pass and touch-and-go are done for three reasons:
- Pilot in training, practicing approach and/or landing.
- When the PIC (pilot in command) misjudges the approach and is concerned that there isn't sufficient runway remaining to stop the aircraft before the end of the runway.
- PIC sees an obstruction on the runway, and decides to abort the landing.

For the AF flight, I think it's the second one. Actually, hope it's the second one!