A plane shrouded in mystery captured the attention of thousands on Wednesday. Nobody knew why a high-altitude plane circled the City of Denver for hours. Now the Navy has some answers. Denver7 tracked IRON99 as it traveled from the West Coast to Oklahoma, where it eventually landed at Tinker Air Force Base, however it spent roughly an hour in Denver, circling in a racetrack-style holding pattern over the city. A clear day allowed thousands to see the flight path and contrails created by the large swept wing, four-engine plane. Denver7 branded it a mystery in a previous report because officials from the Federal Aviation Administration (FAA), U.S. Northern Command (NORTHCOM), U.S. Strategic Command (STRATCOM), North American Aerospace Defense Command (NORAD) and a dozen Air Force Bases could not confirm what the flight may have been. A day later -- after the plane landed -- Navy officials responded to comment on the flight, confirming it did hang over Denver for roughly an hour in a