While both involve handing over your bag at the aircraft door, the primary difference is where you retrieve the bag. "Valet check" is most common on small regional jets with tiny overhead bins. You receive a colorful tag (often red or yellow), leave your bag on a cart at the end of the jet bridge, and—crucially—you pick it up on the jet bridge immediately after deplaning. "Gate check," however, usually occurs on larger planes when overhead space runs out. In this scenario, your bag is tagged with a standard destination sticker and sent to the cargo hold to be retrieved at the baggage claim carousel at your final destination. It is vital to know which one you are doing, as a gate-checked bag will not be available during a layover, whereas a valet-checked bag must be picked up before you enter the terminal.