ARLINGTON — The 48th annual Fly-In at the Arlington Airport kicked off its final day July 9 with feats of motorcycling skill from the Seattle Cossacks Stunt and Drill Team.

Among their configurations of multiple riders piled onto motorcycles that seemed far too small for them all, the Cossacks drew laughter by naming one of their combinations after Boeing’s 787, “only ours is on time.”

After a series of human pyramids atop the bikes, spectators took notice of some of the more distinctive vintage aircraft on site, including a 1955 T-34 Beechcraft that had served as a Navy pilot trainer and range flier based out of Los Alamos, N.M., the latter of which owner Jon Haynes explained to onlookers.

“When the military was doing nuclear testing back then, the range flier would check out the terrain and make sure no one was milling around,” said Haynes, a former commercial pilot. “Those tests were done underground by then, but still, if you were out there, you were going to have a bad day.”

Haynes was drawn to the plane because of history and yellow-and-red paint.

And while Renton resident Bob Dempster’s aircraft looks like a 1924 Douglas World Cruiser, he admitted that it’s actually a replica, albeit one crafted with such painstaking accuracy and attention to detail that what began as a five-year, $350,000 building project has stretched into 15 years and surpassed its original budget a long time ago.

Dempster explained that maintaining period-accurate details qualifies the plane as a home-built experimental aircraft, which in turn required him to fly it for a minimum of 40 hours to certify it.

“That might not seem like a lot, until you realize that the average pilot only flies fifty hours a year, total,” Dempster said. “And with an aircraft like this, you’re manually operating the whole plane when you’re up in the air. I flew it for four hours at a stretch once, and it was the longest four hours of my life. It’s like wrestling with a greased pig.”