to the September 11 attacks, countermeasures were focused on "traditional" hijackings. As such, there were no specific rules for handling suicide hijackings, where aircraft would be used as a weapon. Moreover, military response at the time consisted of multiple uncoordinated units, each with its own set of rules of engagement with no unified command structure. Soon after the attacks, however, new rules of engagement were introduced, authorizing the North American Aerospace Defense Command (NORAD)the Air Force command tasked with protecting U.S. airspaceto shoot down hijacked commercial airliners if the plane is deemed a threat to strategic targets. In 2003, the military stated that fighter pilots exercise this scenario several times a week. Other countries Poland and Russia are among other countries that have had laws or directives for shooting down hijacked planes. However, in September 2008 the Polish Constitutional Court ruled that the Polish rules were unconstitutional, and voided them. International law Tokyo Convention The Convention on Offences and Certain Other Acts Committed on Board Aircraft, known as the Tokyo Convention, is an international treaty which entered force on December 4, 1969. , it has been ratified by 186 parties. Article 11 of the Tokyo Convention states the following: The signatories agree that if there is unlawful takeover of an aircraft, or a threat of it on their territory, then they will take all necessary measures to regain or keep control over an aircraft. The captain can also disembark a suspected person on the territory of any country, where the aircraft lands, and that country must agree to it, as stated in Articles 8 and 12 of the convention. Hague Convention The Convention for the Suppression of Unlawful Seizure of Aircraft (known as the Hague Convention) went into effect on October 14, 1971. , the convention has 185 signatories. Montreal Convention The Montreal Convention is a multilateral treaty adopted by a diplomatic meeting of ICAO member states in 1999. It amended important provisions of the Warsaw Convention's regime concerning compensation for the victims of air disasters. In popular culture The 1997 Hollywood film Air Force One is based on the fictional hijacking of Air Force One. Hijacking is a central theme in the Turbulence movie trilogy. In Mission: Impossible 2, one of the film's antagonists hijacks a plane at the start of the movie. The 2006 film United 93 is based on the real events onboard United Airlines Flight 93