Fuel dumps are instructed under FAA guidance to be done over remote or oceanic areas, or at an altitude at which the dumped fuel can atomize before reaching the ground, although such guidance may be bypassed in dire emergencies, according to the FAA.

Yes, airplanes do dump fuel—a process known as fuel jettisoning—but it is a rare emergency procedure, not a routine occurrence. It is only done when a large, long-haul aircraft (like a Boeing 777 or Airbus A350) needs to return to an airport shortly after takeoff and is too heavy to land safely. If the "maximum takeoff weight" is significantly higher than the "maximum landing weight," landing "heavy" could cause structural damage or a fire. To avoid this, pilots dump fuel to reach a safe landing weight. Per FAA and international environmental guidelines, fuel dumping is typically done at an altitude of at least 5,000 to 6,000 feet, which allows the fuel to vaporize and dissipate into the atmosphere before it can hit the ground or the water. While some fuel is dumped over the ocean to minimize the risk to populated areas, the vast majority of the fuel actually evaporates in the air. Modern "narrow-body" aircraft, like the Boeing 737 or Airbus A320, do not even have fuel-dumping systems; if they have an emergency, they either fly in circles to burn the fuel off or perform a "heavy landing" followed by a mandatory structural inspection.