Park spokeswoman Kyle Patterson said Monday that 20 people and a dog team are also searching for 38-year-old Brian Perri on Mount Meeker.
He has not been heard from since June 30, when he texted a friend with a photo of himself on the summit of the 13,911-foot (4,175-meter) mountain.
Patterson says Perri was day hiking and had no camping equipment. Park officials were notified Thursday that he was missing, and his car was found at a trailhead.
Private drones are banned in national parks. Patterson says authorities allowed the use of the search drone because it can survey areas that are difficult to see from the ground or from larger helicopters.