The game thinks you've landed if you're stuck against the side of a valley, so your engines will refuel and you can hop back up.
Collect the fuel pods, they're the only way you're going to pass the level.
Don't waste fuel, you never know when the next big jump is going to come.
Whenever Tic is rolling along the land itself the fuel meter will quickly fill up.
In the air it's essential that you grab every Hovatron.