Leading aircraftman (or leading aircraftwoman (LACW) is a rank in some 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, between aircraftman

Aircraftman

Aircraftman , or Aircraftwoman , is the lowest rank in the Royal Air Force and the air forces of several other Commonwealth countries....

 and senior aircraftman

Senior Aircraftman

Senior Aircraftman , or Senior Aircraftwoman , is a rank in the Royal Air Force, ranking between Leading Aircraftman and Senior Aircraftman Technician and having a NATO rank code of OR-2. The rank, which is non-supervisory, was introduced on 1 January 1951...

 and having a NATO rank code of OR-2. The rank badge is a horizontal two-bladed propeller

Propeller (aircraft)

Aircraft propellers or airscrews convert rotary motion from piston engines or turboprops to provide propulsive force. They may be fixed or variable pitch. Early aircraft propellers were carved by hand from solid or laminated wood with later propellers being constructed from metal...

.

The rank originated in the 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...

, when it was formed in 1918. It replaced the Royal Flying Corps

Royal Flying Corps

The Royal Flying Corps was the over-land air arm of the British military during most of the First World War. During the early part of the war, the RFC's responsibilities were centred on support of the British Army, via artillery co-operation and photographic reconnaissance...

 rank of air mechanic 1st class (which wore the same badge). It was only a trade classification until 1 January 1951, when it became a rank, although it is non-supervisory.

Leading aircraftman is also a rank in 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...

 (which uses a single chevron rather than a propeller device), 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...

, 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...

, Ghana Air Force

Ghana Air Force

The Ghana Air Force is the air force of the African nation of Ghana. The GAF, along with the Ghanaian Army and Navy, make up the armed forces of Ghana which are controlled by that nation's Ministry of Defence....

 and the Sri Lanka Air Force, and until 1968 was a rank in 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...

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The abbreviation LAC and the propeller device is also used in the New Zealand Air Training Corps

New Zealand Air Training Corps

The Air Training Corps or ATC is one of the three corps in the New Zealand Cadet Forces, the other two being the New Zealand Cadet Corps and Sea Cadet Corps. It is funded in partnership between the RNZAF and communities, and its members are civilians. Members have no obligation to head into the...

, but has a different meaning, standing for leading air cadet. It is not technically a rank (although many units regard it as a very junior NCO rank), it may be awarded to cadets who have attended a minimum of 30 parades, or completed one year in a unit. The rank is generally awarded to those cadets who show obvious leadership skill.