RTD runs busses to the airport every day of the year. With a CollegePass, SkyRide to and from the airport is free. With an EcoPass, SkyRide to the Airport is $2.50 each way (free from the Airport Blvd/40th Ave or the Stapleton Park-n-Ride to DIA). To find out how to get from DU to DIA, check out these Google Maps transit directions. Another option to get to the airport is the Super Shuttle.