Air Force blue is a variety of colours that are a form of blue

Blue

Blue is a colour, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 440–490 nm. It is considered one of the additive primary colours. On the HSV Colour Wheel, the complement of blue is yellow; that is, a colour corresponding to an equal...

. These colours are used by airforces for colour identification.

RAF blue

Air Force blue or RAF blue is a medium shade of the colour azure

Azure (color)

The color bleu de France is displayed at right.Bleu de France is a color that has been associated in heraldry with the Kings of France since the 12th century.-Brandeis blue:...

. The shade derives from the light blue uniforms issued to the newly formed British Royal Air Force

Royal Air Force

The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...

 in 1920, which were influential in the design of the uniforms of some other air force

Air force

An air force, also known in some countries as an air army, is in the broadest sense, the national military organization that primarily conducts aerial warfare. More specifically, it is the branch of a nation's armed services that is responsible for aerial warfare as distinct from an army, navy or...

s around the world. Similar shades are still used in Royal Air Force uniform

Royal Air Force uniform

The Royal Air Force uniform is the standardised military dress worn by members of the Royal Air Force. The predominant colours of Royal Air Force uniforms are blue-grey and Wedgewood blue. Many Commonwealth air forces' uniforms are also based on the RAF pattern, but with nationality shoulder...

s and the Royal Air Force Ensign

Royal Air Force Ensign

The Royal Air Force Ensign is the official flag which is used to represent the Royal Air Force. The Ensign has a field of air force blue with the Union Flag in the canton and the Royal Air Force roundel in the middle of the fly....

.

The choice of blue uniforms for the RAF was the result of a surplus of inexpensive sky blue herringbone

Herringbone (cloth)

Herringbone describes a distinctive V-shaped weaving pattern usually found in twill fabric. It is distinguished from a plain chevron by the break at reversal, which makes it resemble a broken zigzag. The pattern is called herringbone because it resembles the skeleton of a herring fish...

 twill

Twill

Twill is a type of textile weave with a pattern of diagonal parallel ribs . This is done by passing the weft thread over one or more warp threads and then under two or more warp threads and so on, with a "step" or offset between rows to create the characteristic diagonal pattern. Because of this...

 in the United Kingdom, which had been intended for use in the uniforms of Czarist Russian

Russian Empire

The Russian Empire was a state that existed from 1721 until the Russian Revolution of 1917. It was the successor to the Tsardom of Russia and the predecessor of the Soviet Union...

 imperial cavalry

Cavalry

Cavalry or horsemen were soldiers or warriors who fought mounted on horseback. Cavalry were historically the third oldest and the most mobile of the combat arms...

men before the Russian Revolution occurred.

The field

Flag terminology

Flag terminology is a jargon used in vexillology, the study of flags, to describe precisely the parts, patterns, and other attributes of flags and their display.-Description of standard flag parts and terms:...

 of the RAF ensign is specified as "NATO stock no.8305-99-130-4578, Pantone 549C."
The shade of the colour that is shown in the colour info-box is air force blue. Many air forces use shades which closely resemble the shade of air force blue shown above, including the Royal Air Force of the United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 and other nations of the Commonwealth of Nations

Commonwealth of Nations

The Commonwealth of Nations, normally referred to as the Commonwealth and formerly known as the British Commonwealth, is an intergovernmental organisation of fifty-four independent member states...

 primarily inhabited by people of Anglo-Saxon

Anglo-Saxon

Anglo-Saxon may refer to:* Anglo-Saxons, a group that invaded Britain** Old English, their language** Anglo-Saxon England, their history, one of various ships* White Anglo-Saxon Protestant, an ethnicity* Anglo-Saxon economy, modern macroeconomic term...

 ancestry, i.e., the Royal Canadian Air Force

Royal Canadian Air Force

The history of the Royal Canadian Air Force begins in 1920, when the air force was created as the Canadian Air Force . In 1924 the CAF was renamed the Royal Canadian Air Force and granted royal sanction by King George V. The RCAF existed as an independent service until 1968...

, the Royal Australian Air Force

Royal Australian Air Force

The Royal Australian Air Force is the air force branch of the Australian Defence Force. The RAAF was formed in March 1921. It continues the traditions of the Australian Flying Corps , which was formed on 22 October 1912. The RAAF has taken part in many of the 20th century's major conflicts...

, and the Royal New Zealand Air Force

Royal New Zealand Air Force

The Royal New Zealand Air Force is the air arm of the New Zealand Defence Force...

.

USAFA blue

The US Air Force Academy uses a particular shade of blue, subtly different from US Air Force blue, in its sporting and other insignia, described as USAFA blue in official documentation.

Other variations of Air Force Blue

Other air forces of other nations of the Commonwealth, such as the Indian Air Force

Indian Air Force

The Indian Air Force is the air arm of the Indian armed forces. Its primary responsibility is to secure Indian airspace and to conduct aerial warfare during a conflict...

, the Pakistani Air Force and the South African Air Force

South African Air Force

The South African Air Force is the air force of South Africa, with headquarters in Pretoria. It is the world's second oldest independent air force, and its motto is Per Aspera Ad Astra...

, or other air forces of other nations that are not in the Commonwealth, such as the United States Air Force

United States Air Force

The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...

, the French Air Force

French Air Force

The French Air Force , literally Army of the Air) is the air force of the French Armed Forces. It was formed in 1909 as the Service Aéronautique, a service arm of the French Army, then was made an independent military arm in 1933...

, the German Air Force, the Russian Air Force

Russian Air Force

The Russian Air Force is the air force of Russian Military. It is currently under the command of Colonel General Aleksandr Zelin. The Russian Navy has its own air arm, the Russian Naval Aviation, which is the former Soviet Aviatsiya Voyenno Morskogo Flota , or AV-MF).The Air Force was formed from...

, the People's Republic of China Air Force

People's Liberation Army Air Force

The People's Liberation Army Air Force is the aviation branch of the People's Liberation Army, the military of the People's Republic of China...

, the Japanese Air Force

Japan Air Self-Defense Force

The , or JASDF, is the aviation branch of the Japan Self-Defense Forces responsible for the defense of Japanese airspace and other aerospace operations. The JASDF carries out combat air patrols around Japan, while also maintaining an extensive network of ground and air early warning radar systems...

, the Egyptian Air Force

Egyptian Air Force

The Egyptian Air Force, or EAF , is the aviation branch of the Egyptian Armed Forces. The EAF is headed by an Air Marshal . Currently, the commander of the Egyptian Air Force is Air Marshal Reda Mahmoud Hafez Mohamed...

 and the Israeli Air Force

Israeli Air Force

The Israeli Air Force is the air force of the State of Israel and the aerial arm of the Israel Defense Forces. It was founded on May 28, 1948, shortly after the Israeli Declaration of Independence...

, for example, use a wide variety of brighter, lighter, or darker tones of Air Force blue that may differ markedly from the colour shown above. These other variations of Air Force Blue can be seen by inspecting the logos or flags of the air forces in each of the articles linked to above about these different air forces.