WASHINGTON — Over two weeks in July, U.S. Air Force and Marine Corps F-35 joint strike fighters got the chance to fly simulated combat missions together during Red Flag 17-3, marking the first-ever time both the “A” and “B” models of the jet have been employed in the same training exercise.

Although the exercises were a new milestone in F-35 flight operations, the U.S. military has decades of practice operating stealth aircraft. That, former Air Force officials said on Wednesday, is a major reason why it will retain an edge against near-peer competitors like Russia and China, who are just now beginning to fly stealth fighters.

And it’s another reason why stealth technologies deserve continued investment and attention, they said.

“As we see Russia bring on stealth fighters and we see China bring on stealth fighters, we have 40 years of learning how to do this,” Mark Barrett, a retired Air Force two-star general, said during an event hosted by the Mitchell Institute for Aerospace Studies.

Those lessons weren’t always easy, and included the loss of an F-117 Nighthawk that was shot down in 1999 by the former nation of Yugoslavia. But during that time, the Air Force developed a deep understanding of “how to integrate non-stealth and stealth together in packages [and] how we can hide,” Barrett said.