ThrustPac bills their gas-powered backpack propellor as Economical and Eco-Friendly. "Enjoy freedom from the auto or truck and its high cost of operation and confinement. Achieve over 150 miles per gallon on a standard mountain bike without pedaling. And no registration, license or insurance required! At less than one ounce of gas per mile, ThrustPac™ is definitely a GREEN machine. You will have the satisfaction of doing more than your part to reduce emissions while traveling!"
They apparently claim you can get up to 80 mph on a bicycle with the Thrustpac. The device is controlled by a special glove which allows the rider to accelerate or slow down simply by flexing their index finger.
Cycledog asks the questions: Do bicycle tires even have speed ratings? And why is it that I keep hearing George Jetson yelling, "Jane! Stop this crazy thing!" Indeed, what could possibly go wrong?