Fuel

Airplanes almost always have to refuel between flights, and jumbo jets love fuel. A 747 can consume up to a gallon (4 liters) of fuel per second, and "filling up the tanks" takes tens of thousands of gallons of fuel. This huge appetite means that a busy airport can sell millions of gallons of gas every day. At Denver International Airport, fuel comes into the fuel-storage depot through a pipeline at rates that vary from 46,300 to 92,400 gallons per hour (175,264 to 349,772 liters per hour). The depot can also receive fuel from tanker trucks. The fuel is stored in three unloading islands, each with six, 3,000,000-gallon (11,356,235-liter) storage tanks, a meter station and dedicated pump that can handle 300 gallons (1,136 liters) per minute.

In some airports, fuel trucks carry fuel from the storage depot to the airplane for refueling. In others, fuel is pumped through underground pipes directly to the terminals.