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gate guardian

n. (alternative form of gate guard English)

Wikipedia
Gate guardian

A gate guardian or gate guard is a withdrawn piece of equipment, often an aircraft, armoured vehicle, artillery piece, or locomotive, mounted on a plinth and used as a static display near to and forming a symbolic display of "guarding" the main entrance to a site, especially a military base. Commonly, gate guardians outside airbases are decommissioned examples of aircraft that were once based there, or still are. The visual effect is very much like a hobbyist's model, particularly when it is an aircraft mounted on a pole to simulate what it looked like in flight.