Learn to fly

get the glider as soon as possible

You can really milk your distance by plunging straight down, watching your height guage, then soaring back up.

If you have a hard time doing one or two of the challenges but the next ramp height unlocks some higher challenges, try a jump or two on that level, sometimes you'll get one of those, then can use the bonus $ to upgrade, then the lower level ones are simple to beat.

if you have trouble getting the speed challenge, simply fly straight up and straight down. Crappy jump, but you'll hit the speed and get the $.

use the rockets during a transition from downward motion to a more horizontal motion to really gain some speed (the glider actually observes the relationships between thrust, drag, and lift