NATO defines air defence as "all measures designed to nullify or reduce the effectiveness of hostile air action."[1] They include ground and air based weapon systems, associated sensor systems, command and control arrangements and passive measures. It may be used to protect naval, ground and air forces wherever they are. However, for most countries the main effort has tended to be 'homeland defence'. NATO refers to airborne air defence as counter-air and naval air defence as anti-aircraft warfare. Missile defence is an extension of air defence as are initiatives to adapt air defence to the task of intercepting potentially any projectile in flight. In some countries, such as Britain and Germany during the Second World War, the Soviet Union and NATO's Allied Command Europe, ground based air defence and air defence aircraft have been under integrated command and control. However, while overall air defence may be for homeland defence including military facilities, forces in the field, wherever they are, invariably deploy their own air defence capability if there is an air threat. A surface based air defence capability can also be deployed offensively to deny the use of airspace to an opponent. An aircraft is a machine that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil,[1] or in a few cases the downward thrust from jet engines. The human activity that surrounds aircraft is called aviation. Crewed aircraft are flown by an onboard pilot, but unmanned aerial vehicles may be remotely controlled or self-controlled by onboard computers. Aircraft may be classified by different criteria, such as lift type, propulsion, usage and others. Venezuela (Listeni/ˌvɛnəˈzweɪlə/ ven-ə-zwale-ə, Spanish pronunciation: [be.neˈswela]), officially called the Bolivarian Republic of Venezuela[1] (Spanish: República Bolivariana de Venezuela [reˈpu.βlika βoliβaˈɾjana ðe βeneˈswela]), is a country on the northern coast of South America. Venezuela's territory covers around 916,445 square kilometres (353,841 sq mi) with an estimated population of approximately 29,100,000. Venezuela is considered a state with extremely high biodiversity, with habitats ranging from the Andes mountains in the west to the Amazon Basin rainforest in the south, via extensive llanos plains and Caribbean coast in the center and the Orinoco River Delta in the east. Russia Listeni/ˈrʌʃə/ or /ˈrʊʃə/ (Russian: Россия, tr. Rossiya, IPA: [rɐˈsʲijə] ( listen)), also officially known as the Russian Federation[10] (Russian: Российская Федерация, tr. Rossiyskaya Federatsiya, IPA: [rɐˈsʲijskəjə fʲɪdʲɪˈrat͡sɨjə] ( listen)), is a country in northern Eurasia.[11] It is a federal semi-presidential republic, comprising 83 federal subjects. From northwest to southeast, Russia shares land borders with Norway, Finland, Estonia, Latvia, Lithuania and Poland (both with Kaliningrad Oblast), Belarus, Ukraine, Georgia, Azerbaijan, Kazakhstan, China, Mongolia, and North Korea. It shares maritime borders with Japan by the Sea of Okhotsk and the US state of Alaska across the Bering Strait. At 17,075,400 square kilometres (6,592,800 sq mi), Russia is the largest country in the world, covering more than one-eighth of the Earth's inhabited land area. Russia is also the world's ninth most populous nation with 143 million people as of 2012.[12] Extending across the entirety of northern Asia and much of Eastern Europe, Russia spans nine time zones and incorporates a wide range of environments and landforms. The United States Air Force (USAF) is the aerial warfare service branch of the United States Armed Forces and one of the seven American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on 18 September 1947 under the National Security Act of 1947.[5] It is the most recent branch of the U.S. military to be formed, and is the largest and one of the world's most technologically advanced air forces. The USAF articulates its core functions as Nuclear Deterrence Operations, Special Operations, Air Superiority, Global Integrated ISR, Space Superiority, Command and Control, Cyberspace Superiority, Personnel Recovery, Global Precision Attack, Building Partnerships, Rapid Global Mobility and Agile Combat Support.[6] The U.S. Air Force is a military service within the Department of the Air Force, one of the three military departments of the Department of Defense. The USAF is headed by the civilian Secretary of the Air Force, who is appointed by the President with the advice and consent of the Senate. The highest-ranking military officer in the Department of the Air Force is the Chief of Staff of the Air Force who exercises supervision over Air Force units, and serves as a member of the Joint Chiefs of Staff.

• published: 19 Sep 2013
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