SAN DIEGO (AP) — The Marine Corps is forming the first squadron of pilots to fly the next-generation strike fighter jet, months after lawmakers raised concern that there was a rush to end the testing of an aircraft hit with technical problems.

So far two veteran pilots of the 3rd Marine Aircraft Wing have been trained to fly the F- 35B. They are becoming the first members of the Marine Fighter Attack Squadron 121 that will debut at a ceremony Tuesday at the Marine Corps Air Station in Yuma, Ariz.

The first F-35B arrived Friday and 15 more are slated to arrive over the next year. The Defense Department has pumped a half a billion dollars into upgrading the facilities, hangars and runways at the base to make way for the next-generation fighter jet, officials said.

The pilots of the new squadron are expected to fly the aircraft by year’s end.

The Marines are the first in the military taking the steps toward putting the planes in operation.

The F-35B would replace Cold War-era aircraft such as the F/A-18 Hornet and AV-8B Harrier.