Aerial warfare is the use of aircraft and other flying machines for the purposes of warfare. Having developed from using unpowered observation balloons in the 18th century, aerial warfare has become a high-technology affair that has lead to air travel and many advances in propulsion, radar, carbon fibers, and more.
Some minor use was made of balloons in the 18th and 19th Century. The first instance was by the French Aerostatic Corps in 1794, who used a tethered balloon to gain a vantage point . Later, balloons were allowed to drift over enemy defences for observation purposes. However, balloons could often be driven off by smoke and so military aviation did not play a significant part in warfare until World War I.
Before World War I
The armies of many countries evaluated the use of aircraft for observation purposes. Naval aviation was pursued as well; several tests were made in which floatplanes were launched by catapult from ships at sea, and recovered later by crane.
The U.S. Navy had been interested in naval aviation since the turn of the 20th century. In 1910-1911, the Navy conducted experiments which proved the practicality of carrier-based aviation. On November 14, 1910, near Hampton Roads, Virginia, civilian pilot Eugene Ely took off from a wooden platform installed on the scout cruiser USS Birmingham (CL-2). He landed safely on shore a few minutes later. Ely proved several months later that it was also possible to land on a ship. On January 18, 1911, he landed on a platform attached to the American cruiser USS Pennsylvania (ACR-4) in San Francisco harbour.
World War I
Initially during that war both sides made use of tethered balloons and airplanes for observation purposes, both for information gathering and directing of artillery fire. A desire to prevent enemy observation led to airplane pilots attacking other airplanes and balloons, initially with small arms carried in the cockpit, and later with machine guns mounted on the aircraft. Both sides also made use of aircraft for bombing, strafing and dropping of propaganda. The German military made use of Zeppelins to drop bombs on Britain.
By the end of the war airplanes had become specialised into bombers, fighters and observation aircraft.
Between the wars
Between 1918 and 1939 aircraft technology developed very rapidly. In 1918 most aircraft were biplanes with wooden frames, canvas skins, wire rigging and air-cooled engines. By 1939 most military aircraft were metal framed monoplanes, often with stressed skins and liquid cooled engines. Top speeds had tripled; altitudes doubled (and oxygen masks become commonplace); ranges and payloads of bombers increased enormously. Most industrial countries also created air forces separate from the army and navy.
Some theorists, especially in Britain, considered that aircraft would become the dominant military arm in the future. They imagined that a future war would be won entirely by the destruction of the enemy's military and industrial capability from the air. Others, such as General Billy Mitchell in the United States, saw the potential of air power to neutralize the striking power of naval surface fleets.
Germany was banned from possessing a significant air force by the terms of the WWI armistice. The German military continued to train its soldiers as pilots clandestinely until Hitler was ready to openly defy the ban.
World War II
Military aviation came into its own during the Second World War. The increased performance, range, and payload of contemporary aircraft meant that air power could move beyond the novelty applications of World War I, becoming a central striking force for all the combatant nations.
Over the course of the war, several distinct roles emerged for the application of air power.
Strategic bombing of civilian targets from the air was a strategy first proposed by the Italian theorist General Giulio Douhet. In his book The Command of the Air (1921), Douhet argued that future military leaders could avoid falling into bloody World War I-style trench stalemates by using aviation to strike past the enemy's forces directly at their vulnerable civilian population. Douhet believed that such strikes would cause these populations to rise up in revolt and overthrow their governments to stop the bombing.
Douhet's ideas were paralleled by other military theorists who emerged from World War I, including Sir Hugh Trenchard in Britain.
In the interwar period, Britain and the United States became the most enthusiastic supporters of the strategic bombing theory, with each nation building specialized heavy aircraft specifically for this task.
Tactical air support
By contrast with the British strategists, the primary purpose of the German Luftwaffe was to support the ground army. This accounted for the presence of large numbers of dive bombers in the make-up, and the scarcity of long-range heavy bombers. This 'flying artillery' greatly assisted in the successes of the German Army in the Battle of France (1940). Hitler determine that air superiority was a requirement for the invasion of Britain. When this was a not achieved in the Battle of Britain during the summer of 1940 the invasion was cancelled, making this the first major battle whose outcome was determined primarily in the air.
The aircraft carrier first became important in World War II, particularly in the Battle of Midway, where American aircraft sunk four Japanese carriers (at a cost to the Americans of one carrier sunk and one disabled, plus some other ships). In this battle, neither force was in visual contact with the other, and all fighting was carried out by aircraft - a military first.
Military aviation in the post-war years was dominated by the needs of the Cold War. The post-war years saw the almost total conversion of combat aircraft to jet power, which resulted in enormous increases in speeds and altitudes of aircraft. Until the advent of the Intercontinental Ballistic Missile major powers relied on high-altitude bombers to deliver their newly-developed nuclear deterrent; each country strived to develop the technology of bombers and the high-altitude fighters that could intercept them.
The Americans developed and made extensive use of the high-altitude observation aircraft for intelligence-gathering. U-2, and later the SR-71 Blackbird were developed in great secrecy. The U-2 at its time was supposed to be invulnerable to defensive measures, due to its extreme altitude. It therefore came as a great shock when the Soviets downed one piloted by Gary Powers with a ground-to-air missile.
In the 70s and 80s it became clear that speed and altitude was not enough to protect a bomber against air defences. The emphasis shifted therefore to manouverable attack aircraft that could fly 'under the radar', at altitudes of a few hundred feet.
The development of the helicopter revolutionised the aerial support of ground forces. A helicopter could deliver troops quickly to areas inaccessible to fixed-wing aircraft - and, unlike paratroops, they could be recovered again. This led to an entirely new class of airmobile troops (which the US referred to as Air Cavalry), able to land unexpectedly, strike, and leave again. Such tactics played a major part in the Vietnam War.