Bottom position of the Airborne Lunge...(above^)

Bottom position of the Single leg Squat...(above^)

I know it looks like my heel is touching but it isn't.

As you can see there is a big difference between these two movements - airborne lunge a shorter movement but might lend itself to an aggressive shin angle and strong push off - Single leg squat a full range of motion (and it is this deep hip position that actually fires off the glute) and a pretty cool looking move.  One of the keys is to maintain tension at the bottom and not to "sink" all the way down  by relaxing (not a good idea).