In aviation, a preflight checklist is a list of tasks that should be performed by pilots and aircrew prior to takeoff. Its purpose is to improve flight safety by ensuring that no important tasks are forgotten.

The pre-flight check (or walk-around) is the pilot's final line of defense against mechanical failure and is a non-negotiable legal requirement in aviation. Its primary importance lies in identifying "latent defects"—issues that may have occurred during the previous flight or while the plane was parked. During the check, pilots look for structural issues like loose rivets, bird strikes, or fluid leaks (oil, fuel, or hydraulic) that might not be visible from the cockpit instruments. They verify that the pitot tubes and static ports (which provide airspeed and altitude data) are clear of obstructions like ice or insect nests, which have caused major crashes in the past. It also ensures that the control surfaces (flaps, ailerons, rudder) move freely and that the tires are properly inflated and not worn to the point of failure. Beyond safety, the check is a psychological "reset" for the pilot, allowing them to transition into a focused "flight mode" and ensuring they are personally familiar with the specific quirks of the aircraft they are about to command.