An F-35C Naval variant (US Navy photo)

An F-35C Naval variant (US Navy photo)

In an important milestone for the F-35 program, Lockheed Martin recently delivered four more operational aircraft to the U.S. Air Force and Marine Corps., giving the Department of Defense more operational F-35s than test aircraft for the first time.

A total of nine F-35s have been delivered for the year, giving the DOD a total of 30 aircraft fleet-wide. Of these, 16 are operational, and 14 are test planes.

“To date, the F-35 program has focused on system development and flight testing while most recently transitioning to low rate initial production,” said Orlando Carvalho, Lockheed Martin’s executive vice president and general manager for the F-35 program, in a statement. “These deliveries illustrate the program’s natural progression and maturation that is taking place on a daily basis.”

The four latest aircraft will be ferried to Eglin Air Force Base, Fla. The Defense Department has eight test F-35s at Naval Air Station Patuxent River, Md., and six test aircraft at Edwards Air Force Base, Calif.

Three of the jets are F-35A conventional takeoff and landing (CTOL) variants and will be assigned to the U.S. Air Force’s 33d Fighter Wing. One F-35B short takeoff and vertical landing (STOVL) aircraft will be assigned to the 2nd Marine Aircraft Wing’s Marine Fighter/Attack Training Squadron 501. Once at Eglin, the 5th Generation fighters will be used for pilot and maintainer training at the base’s F-35 Integrated Training Center.

The F-35 is one of the most advanced fighter plans ever built. It is a fifth generation fighter with stealth features and ultra-modern avionics and computer/electronics equipment.

The aircraft is designed for both air-to-air and ground attack and will replace the F-16 for the Air Force, the F/A-18 C/D variants for the Navy, and the F/A-18 and AV8-B Harrier for the Marine Corps. Nine other countries are also part of the program. In the Air Force, the F-35 may also replace the A-10 in some roles, but the A-10 is expect to remain in service until about 2028.