Denver International Airport, located in Denver, Colorado, is the largest airport in the United States by total area (54 square miles) and is among the busiest airports in the world. With more than 40,000 public parking spaces, the Denver airport provides a range of choices to meet traveler needs.The cost of parking at the airport depends on parking option chosen and the duration of stay. When using the DIA Reserved Parking to guarantee a parking space, clients will be charged with a $4 daily reservation fee, which will be collected at the time of reservation. 2  The parking fee will be collected upon exit. 3  Lost tickets will be charged.