AirCorps Aviation, a Bemidji company that restores World War II aircraft, frequently has people reach out to it with military artifacts. Often, those offering up mementos believe their pieces have great historical value.

The company has earned a niche in the “Warbirds” community of World War II aircraft aficionados as an authority on P-51 Mustangs, an iconic World War II fighter plane. People often call, believing they have rare and important historical microfilms of engineering drawings. Most are little more than junk.

But last year, Ester Aube, the company’s data and library specialist, got a call from a retired Ohio engineer named Ken Jungeberg. Jungeberg once worked at North American Aviation in Columbus, which manufactured the P-51 Mustangs, and had original engineering drawings of the plane.

And Jungeberg wanted to know: Was the Bemidji company interested in those originals, since the drawings are typically only seen on dark and incomplete microfilm?

Intrigued, Aube asked him to mail her some of the drawings. When she opened a tube filled with 14 intricate pencil drawings of the planes, it took her back in history to 80 years ago.

“I freaked out,” Aube said. “Because nobody had really seen these before. I almost started crying when I saw one of these drawings. It was the throttle quadrant drawing from the P-51 Mustang. I knew what it looked like on microfilm. It was really dark. You couldn’t read much of the important information. And it blew me away, that I was here holding the exact piece of paper photographed on that microfilm.”

The drawings tell a remarkable behind-the-scenes tale of the war effort on the home front. The military asked North American Aviation in 1940 to build P-40 Warhawks, a Curtiss-Wright-designed plane. North American Aviation demurred, wanting to build its own version. The military gave the company 120 days to build that new version. The first prototype was designed and built in 117 days. Many of Jungeberg’s drawings were from the original 117-day project.

Aube and Erik Hokuf, the general manager of AirCorps Aviation, flew to Ohio to see Jungeberg’s collection of drawings, which he kept from being destroyed in the 1980s. Some of the crates hadn’t been opened in decades. Jungeberg had even saved original packing slips.

“When you put your hands on it, you feel like you shouldn’t touch them, but it sinks in when you can see the pencil on the paper,” Hokuf said. “It just gives you chills. It brings you back to World War II.”

Jungeberg transferred ownership of the thousands of drawings to AirCorps Aviation, and the company is in the midst of collating, digitizing and archiving them. The drawings have historical value and also logistical value for the company, which restores planes to flying condition with much the same sounds and at the same speeds as during the war.

In 1940, only 3,600 aircraft were produced in the United States. By 1945, American companies had produced nearly 300,000 in the intervening five years.

The story is particularly relevant today, when America finds itself in a different type of war, against COVID-19.

“The country is trying to mobilize to make masks and vents and medical supplies and retraining medical staff, and all those things are exactly what happened during World War II,” Hokuf said. “We banded together as a country and a world.”

“When you touch those drawings, those are the stories you can feel,” he added. “It’s a time portal back to those days when as a country we put our differences aside and focused on one mission.”