Passengers had to take shelter in bathrooms and stairwells for about a half-hour Tuesday after the warning was issued. The National Weather Service said a confirmed tornado was spotted in the area.
Television coverage showed the airport's normally busy concourse was completely empty during the warning period.
As the storm passed, police briefly blocked traffic from Interstate 70 to Pena Boulevard, which connects the interstate to the airport. Dark clouds blanketed parts of the horizon over the plains to the east.
Grayson Schaffer, a senior editor at Outside Magazine, was at the airport when the tornado arrived.
"The TSA comes through telling everyone that they need to take shelter immediately because there's a tornado bearing down on the airport at that very moment," Schaffer said.
Schaffer, who is working on a story for Outside about tornado chasers, went outside to get a closer look at the storm.
"This thing was forming right above us," he said. "It was was, I'm told, a pretty unique perspective to see a vortex like this forming."
Severe thunderstorms could still produce some strong winds and hail in the area and across Colorado's eastern plains.