Area 51 just got a little more mysterious. 

The US Air Force’s top-secret Boeing 737-200 aircraft, also known as the RAT55 jet, was spotted soaring over Nevada’s Groom Lake facility, confirming long-rumored ties to the classified base. 

From 26 miles away atop Tikaboo Peak, a mountain in Nevada, plane-obsessed photographer Michael Rokita recorded fuzzy footage of the RAT55, which is used as a radar testbed, pulling off touch-and-go maneuvers and a landing on Runway 32, according to the Daily Mail.

Moments later, the jet rolled into Hangar 18 as the huge doors parted like a scene straight out of a sci-fi movie. 

Recognizable by its rotund nose and humpbacked profile, the RAT55 probes the stealth of other planes midflight — a covert gig that may have backed the RQ-80 drone.

Normally in secret, the RAT55 prowls prohibited airspace near Edwards Air Force Base, ghosting flight trackers by turning its transponder off. 

As per the Daily Mail, Rokita confirmed RAT55’s call sign is “Saber 98,” a smoking-gun link tying the mysterious jet to Area 51’s secretive Hangar 18. 

Dodging his devices’ power failures and the desert’s sweltering heat with a Nikon P1000 and a bespoke binocular-smartphone rig, he snapped proof of the radar-testing aircraft.

The jet is rumored to size up everything from B-2s to stealth prototypes like the B-21 Raider. 

RAT55 hardly ever leaves Nevada, but spotting it rolling into the infamous Hangar 18 just stokes decades of alien and black-budget rumors.

Back in April, The Post reported on Jerry Freeman, a cultural researcher who accidentally wandered into a restricted corner of Area 51 — and lived to tell the tale. 

On a 1996 quest to track lost 1849 Gold Rush journals near the Nevada base, Freeman snuck in undercover at night — and instead of old writings, he may have stumbled on an alien spacecraft, he told UFO researcher George Knapp.

“It looked like a dry lakebed to me, nothing else, but at night it was a different story,” Freeman said to Knapp.

“I could clearly see what were security lights on the perimeters and I could see lights that opened and closed near the center of the lake,” the anthropologist went on.

Freeman only got a few minutes to watch — but felt the ground rumble beneath him, a sure sign that something top-secret was being tested.

For decades, Area 51 was off limits and off the record — until 2013, when the feds finally admitted it existed.

Nearly 30 years after Freeman’s brush with the base, conspiracy theories linking it to aliens are still flying.