In the United Kingdom Royal Air Force and the other air forces of the Commonwealth, from where much air force terminology emanated, an aircraft flight, in the first decades of air forces, was commanded by a flight lieutenant, a rank equivalent to captain in armies and other air forces, or a naval lieutenant. More recently, however, it has become common for a flight to be led by a squadron leader—a formal rank distinct from a squadron commander—equivalent to an army major or naval lieutenant commander.