MANKATO — A Minneapolis man in Mankato for the Minnesota Air Spectacular said he was only a few feet away from a Mayo Clinic helicopter when its blades started whirring and its engine powered up.

Rotor Technologies A New Hampshire company is recycling old helicopters into the world’s largest drones, hoping to create a new class of unmanned aerial vehicles.

Fritzler’s old squadron number had been painted over with a different squadron’s number, but he still recognized the helicopter as the one he flew.