Remove before flight is a safety warning often seen on removable aircraft and spacecraft components, typically in the form of a red ribbon, to indicate that a device, such as a protective cover or a pin to prevent the movement of mechanical parts, is only used when the aircraft is on the ground (parked or taxiing). On small general aviation aircraft, this may include a pitot tube cover or a control lock. The warning appears in English only. Similar ribbons labelled pull to arm or similar are found on missiles and other weapon systems that are not mounted on aircraft.
In some cases, non-removal of a labelled part has caused airplane crashes, like that of Aeroperú Flight 603.
It is common to see key rings, T-shirts, bag tags, belts and other such products with this ribbon, especially for people who work in aviation or aviation enthusiasts.