To do this, you must be paired up with a human partner. At Rainbow Road or Luigi's Circuit 2, 150cc or higher, do a Double Dash off the starting line. While that boost is still in effect, hit the jump boost (at 50 or 100cc the dash wears off before you reach the boost). When you land, the back player will stay in his flying position until you fall off, you get hit by an item, you use an item, or you go on the elevator.
Submitted by: Zanto