North Korea possesses the technological wherewithal to develop a nuclear bomb, launch devastating cyberattacks, and even hurl rockets toward its enemies. Yet it can't manage to put together an airline that isn't heavily stocked with Cold War-era Russian airliners.

That said, the Air Koryo fleet is pretty cool in a retro kind of way, and a passionate band of aviation buffs happily spend their days taking joyrides. “They’re beautiful,” says Arthur Mebius. “These planes still have the original interiors they were delivered with.”

Air Koryo started ferrying people between Pyongyang and Moscow in 1950. After the fall of the Soviet Union, sanctions and lack of funds kept the the state-owned airline from buying more than a few new planes. Today its fleet of 15 aircraft includes the Ilyushin 62, Kim Jong Un's personal favorite. The EU banned the airline in 2006 amid safety and maintenance concerns, and flights to Bangok, Kuala Lumpur, and Kuwait City ended last year. But the airline still makes regular flights to China and Russia.

Most of the planes date to the 1960s (though a few planes, including a snazzy Tupolev Tu 204-300, entered line up more recently), the service is iffy, and the food sucks. So you can see why some people call Air Koryo "the one-star airline." But Mebius and air travel aficionados liken a flight on Air Koryo to reliving the golden age of air travel.

Mebius read about the vintage fleet in 2015 and booked a $1,600 aviation tour through British agency Juche Travel. After flying from Amsterdam to Beijing, he hopped an Air Koryo flight to Pyongyang. He loved it so much he returned two more times.

All told, Mebius has made 24 flights aboard 10 different kinds of aircraft, most of which were all but empty. The joyrides cost about $200 apiece, and although the aviation tourists occasionally take in the sights, the flights are the main attraction. Simply taking off felt like a grand affair. The pilot's pre-flight routine included poking the tires to ensure proper inflation. Flight attendants in dated uniforms helped passengers get settled. And then the engines started with a deafening roar. “It’s kind of scary,” Mebius says. “Add that with the noise, the dated design, and this strange communist country, and you have a party.”

Once aloft, Mebius roamed the plane with his Fuji X100T. He eventually stopped asking the flight crew if he could take their photo to get more candid shots. “To North Koreans, a good photos is when somebody is looking into a camera, posed and proud and aware of the camera," he says. "Of course, this is not what I wanted."

His quiet, sunlit images look like they were shot decades ago, adding to the sense of mystery of a country that already seems like something out of the past.

Mebius' series Dear Sky is available as a photo book on June 20.