He’s right that it’s a stunt, but wrong about fill time. Tesla’s engineering VP says filling all 600 liters takes 6 to 7 hours today, from an external nitrogen supply. A compressor in the car would need about 90 kWh: about 18 hours at 5 kW, the power of a large portable dive-air compressor. Only a compressor of about 0.5 kW would take a week. The Thrust version’s 200-liter tank gives about 5 to 6 seconds of thrust. If you want the car to fly, my first fix as a chemist would be a denser propellant. The 1961 Bell Rocket Belt flew on 90% hydrogen peroxide, broken down on a catalyst into steam and oxygen at about 740 °C. We started Solugen making peroxide. At 90%, it’s a strong oxidizer that can set clothing and oil on fire on contact. You wouldn’t put that in a car. The best use case for compressed gas and a few seconds of thrust is braking. Tesla says the thrusters push 4 to 5 times harder than the tires grip. Fired forward, that would cut the Roadster’s stop from 60 mph from about 95 feet to under 20, in under half a second. Tesla says the tank holds up to 10,000 psi. Cars already carry gas that compressed for years: some airbags inflate from sealed bottles of argon and helium filled to as much as 10,000 psi, built to work for more than 10 years. For a brake used once a year, the 6-to-7-hour refill doesn’t matter.