I disagree. I hate flipping on a trampoline because I always feel there isn't a large enough landing if I drift a little. I learned backflips off the hips of landings. They're so easy. Just do them on a snowy or warm day when the snow's soft. Once you do 10 of them you'll be landing them no prob. I still havent taken them to jumps but off the side hits they're pretty fun.
Well then it's pretty easy as long as you have backflipped on a trampoline before. I'm talking without a board though. Just make sure to lead with your head and not your shoulders. If you do then you'll start to twist. Also try to make sure your board leaves even off the jump too. It'll keep you from spinning too.
I learned on an airbag first, then realized how easy it is and can do it off of most jumps now but i don't like doing it on icy days. When going off of the jump wind your arms back and as you hit the lip pop off with your heel edge and swing your head back and tuck your knees when you get upside down. Then you should beable to spot and land it.