Instructions
Push forward on the left stick to pick up speed and head to one of the ramps.
Hold down the right trigger to "pump" as you approach the first ramp.
Release the right trigger just before you go up the ramp.
Turn in midair and come back down. At the bottom, press the right trigger again and pump to the opposite ramp.
Continue this process. You will gain more air each time you go up a ramp until you pass the challenge.