In some two-seat fighter aircraft such as the Tornado, the operational conversion unit (OCU) aircraft can be created by duplicating flight controls in the rear cockpit. In a normally single-seat aircraft, a second cockpit can be built behind the original cockpit (e.g. the TA-4S variant of the A-4SU Super Skyhawk) or the cockpit can be extended to place the instructor in a second seat behind the pilot. Once they are qualified to fly a specific type of aircraft, pilots will continue with regular training exercises to maintain qualifications on that aircraft and to improve their skills, for example the USAF's "Red Flag" exercises. Deployments of small flights of aircraft together with support staff and equipment to exercises conducted by other nations can be used to develop fighting skills and interservice and inter unit competitions in bombing and gunnery between units can also be used to develop those skills.