Grounding ensures electrical continuity between the aircraft and the earth. Static electricity resulting from the flight or the environmental conditions on ground (wind with dust, sand, etc...) is discharged to the earth through the tires.

Airplanes are "grounded" (or more accurately, bonded) before refueling to prevent static electricity sparks from igniting fuel vapors. As fuel flows through a hose at high speed, it generates friction against the hose's inner walls, creating a buildup of static electricity. Additionally, the airplane itself accumulates a static charge during flight from friction with the air. If the refueling nozzle touches the plane's fuel tank without a prior electrical connection, a spark could jump between them, potentially causing an explosion. To prevent this, a bonding cable is attached between the refueling vehicle and the aircraft's frame, ensuring they are at the same electrical potential. While "grounding" (connecting to the physical earth) was the old standard, the industry has shifted toward "bonding" (connecting the two objects to each other) because it is more effective at neutralizing the specific voltage difference that causes sparks, particularly in inclement weather where a ground cable might actually attract lightning.