True, but getting an aircraft to fly steady at 5m above the ground requires some serious piloting skills. We're not talking about a stunt rider jumping two ramps, we're talking about a bike dropping out of a helo or an airplane onto flat ground. Hence why using the rules for rocket boosters and gliding systems make sense; if you can get the pilot to maintain an altitude of 5m while you drop out of it use the rocket booster rules. Otherwise, it might be a good idea to mount a gliding system, is all I'm saying.