A forced landing of an aircraft occurs typically as a result of accident; see emergency landings. But a plane can also be forced to land with little or no damage by another plane, as when a civilian airliner strays off course into hostile foreign territory.
- The customary procedure is for the military plane to approach the airliner from below and to the left, where his plane is easily visible from the left seat where pilots sit. The the forcing plane waggles his wings to signal the demand for a forced landing. 
International law regulates the treatment of intruding aircraft:
- ... aircraft that fail to identify themselves, enter the airspace without a necessary permission, deny to follow a prescribed route, head towards a prohibited zone, or violate of a prohibition of flight may, by strict observance of the relevant standards and procedures, as a last resort, be intercepted, identified, escorted to the adequate route or out of the prohibited airspace, or forced to land by military aircraft of the territorial state. 
- ... the international requirements for making an intruding plane follow an air-force escort to the ground - moving in front and to the left, where the civilian pilot can see the escort, and waggling the fighter's wings. The Washingtonian November, 1985 - Page 153-154
- An Assessment of the Destruction of Rogue Civil Aircraft under International Law and Constitutional Law