In JAK 3 when you get light flight what do you do

The triangle button lets you flap your wings. Every time you flap your wings, you use a portion of your light eco meter. The first flap will be the most powerful and every flap after that you will sink lower and lower until, after 4 or 5 flaps, you can't fly any more. So it's not really sustained flight; it's more like extended double jumping. An interesting cheat: if you have unlimited light eco, you can press triangle-circle-triangle-circle over and over again to fly indefinitely. You have to get the timing right, which takes a little practice, but once you do it's very cool.