I can't say I've ever needed to know the exact amount of time I've spent in the air when doing a jump, but maybe that's because mine are pretty insignificant. If your airtime can be measured in seconds, rather than milliseconds, then you can measure it to the nearest 0.25 seconds with the HangTimer watch. And if you wanted to check that that last drop you did really was your biggest ever, Hangtimer stores your hugest airtime (as well as your average, and last ten - for information addicts).
