Last month, a replica World War One plane finally took to the skies above a Royal Air Force station in Scotland. “Every single nut and bolt has been checked, every single bracket has been checked, every single piece of wire has been checked. When you’re going to fly it, it has to be done right,” chairman Mike Harper told the BBC. “I’m used to flying modern aeroplanes from the 50s and 60s—the classics—and they’re very different from this aeroplane to fly. This is very much more of a challenge,” aircraft inspector Tim Rayner, who pilots the test flights, told the BBC after May’s 15-minute flight.