Aircraft manufacturing remained a high priority throughout the war for all the key combatants and was a major part of their economic output. Women, and in Germany slave labour, were extensively employed due to the military call-up of able-bodied men.

Due to the threat of bombing, especially in Europe, manufacturing became progressively more dispersed. When British and American bombing raids started in earnest, Germany moved much of its production into underground factories.

Strategic materials such as aluminium for airframes and petroleum oil for fuel were in limited supply and soon became scarce. Many manufacturers, especially in the Soviet Union and, later on, in Germany turned to more readily-available raw materials such as timber and coal. The de Havilland Mosquito fighter-bomber was a rare British example of a wooden aeroplane.
At the outbreak of war there were relatively few aerodromes capable of supporting military aircraft operations. Land-based aircraft with retracting undercarriage had superior performance to the equivalent seaplanes, leading to the widespread construction of aerodromes throughout all theatres of campaign. After the war many of these would become civil airports, providing the basis for a move of long-range passenger flights from flying boats to landplanes.

The increasing sophistication of warplanes meant that ground facilities also became more sophisticated. The high-powered engines in use could no longer be started by hand-swinging the propeller, but powered starting systems had to be provided, whether mechanical as with the Hucks starter or electrical as with the wheeled battery pack or trolley accumulator used for aircraft such as the Spitfire, which had an inbuilt electric starter motor.

Aviation during this period was dominated by the conduct of the war, and the war in turn by air power. Aviation was heavily involved in the development of military technologies, strategies, tactics and events throughout the war.

At the outbreak of the war in Europe in 1939, the German Luftwaffe had amassed an attack force of modern all-metal cantilever monoplanes designed to support the Blitzkrieg style of warfare at relatively short range and manufactured by a large and organised industry. Pilots had been well-trained, both in flying clubs and in some cases the Spanish Civil War. Other European air forces, especially the British RAF were struggling to re-equip with similarly modern types and to train up aircrew. Early German successes, with the notable assistance of the Junkers Ju 87 Stuka dive-bomber, overran Europe and left Britain open to attack.

During the ensuing Battle of Britain, the British fighter squadrons had to quickly relearn the old tactical lessons from the first war. Initially the RAF fighters flew in a tight three-fighter arrowhead formation, soon changing to the looser four-aircraft arrangement which the Germans called the "finger-four." They soon also relearned the value of climbing above your opponent before attacking. At the same time, the development of an early radar warning system by the British provided a new way to track German attack formations as they gathered over the European coast and flew across the English Channel. The radio communications, provided to every pilot, also required new protocols such as radio silence before engaging the enemy.

Later on, the British and Americans developed large long-range heavy bombers, causing great damage to the German war effort and substantial casualties. While the British favoured unescorted night bombing, the Americans preferred to mount daytime raids, escorted by long-range fighters.

In the Pacific war, both sides made extensive use of aircraft carriers and carrier-to-carrier engagements became pivotal turning points in several campaigns.

• Aviation in World War I
• List of aircraft of World War II