In 2015 the F-35 lost repeatedly in mock dogfights with F-16s because it couldn't turn well enough, a test pilot wrote in an official report.

But new videos leaked from the US Air Force's F-35 demo or stunt flying team show the jet making head-spinning turns that older jets could never hit.

A former F-35 squadron commander told Business Insider that the jet has become an excellent dogfighter, and the new moves show it.

Early in its combat testing, a test pilot's damning report leaked to the press and exposed the world's most expensive weapons system, the F-35, as a bad dogfighter that the F-16 routinely trounced in mock battles.

But new videos leaked from the US Air Force's F-35 demo or stunt flying team show the jet making head-spinning turns that older jets could never hit.

In 2015, the test pilot's write up of the jet's combat performance obliterated the idea of F-35 as a capable dogfighter due to a glaring flaw: Weak maneuverability.

"Overall, the most noticeable characteristic of the F-35A in a visual engagement was its lack of energy maneuverability," the pilot wrote.

Read more: Here's why the F-35 once lost to F-16s, and how it made a stunning comeback

"The F-35 was at a distinct energy disadvantage in a turning fight and operators would quickly learn it isn't an ideal regime... Though the aircraft has proven it is capable of high AOA [angle of attack] flight, it wasn't effective for killing or surviving attacks primarily due to a lack of energy maneuverability," he continued.

Furthermore, according to the pilot, there was basically nothing the F-35 could do to escape getting killed by the F-16's gun. Any move he tried to escape the F-35's cannon read as "predictable" and saw the pilot taking a loss.

But the F-35 program and its role in dogfights hadn't been as well figured out back then.

Since then, the F-35 has mopped up in simulated dogfights with a 15-1 kill ratio. According to retired Lt. Col. David Berke, who commanded a squadron of F-35s and flew an F-22 — the US's most agile, best dogfighter — the jet has undergone somewhat of a revolution.

New moves, new rules

In the video, the F-35 pilot takes the plane inverted, hits a tight loop, and appears to pause in mid-air as he enters a flat spin that makes his hundred-million-dollar jet appear like a leaf floating down towards earth. (Really better to watch than read about it.)

The flat spin move is often used by F-22 and Russian fighter pilots to show off the intense ability of their planes to sling the nose around in any direction they wish.

According to Berke, this F-35 stunt "demonstrates what the pilots and the people around the aircraft have always known: It's vastly superior to almost anything out there," in terms of agility.

Furthermore, according to Berke, an F-16 could not hit the move shown in the demo team's video.

Read more: A new generation of F-35 pilots are coming, and they'll solve the fighter's biggest problem

Berke and others close to the F-35 program have described to Business Insider a kind of breakthrough in the maneuvering of the F-35 throughout its development.

Berke said the video proves that the F-35 is a "highly maneuverable, highly effective dogfighting platform," but even still, he wouldn't use that exact maneuver in a real dogfight.

The flat spin is "not an effective dogfighting maneuver, and in some cases, you would avoid doing that." David Berke in an F-22 Courtesy of David Berke

"If me and you were dogfighting and we’re 2 miles away, and I had a wingman 5 miles away, you’d be super slow and predictable and easy for him to find," due to executing the move, said Berke.

But despite the F-35's impressive moves and ability to win dogfights, Berke said he'd stay on mission and try to score kills that take better advantage of the jet's stealth.

Read more: Russian fighter pilot says he beat an F-22 in a mock dogfight and locked onto it, but the Pentagon threw cold water on the claims

"I want to avoid getting into a dogfight, but if I had to I’m going to be able to outmaneuver most other aircraft," he said.

After all, the F-35's makers never intended it as a straight World War II-era Red Baron killer, but a rethink of aerial combat as a whole.