Operating out of Delta Airlines DEN Terminals Concourse A is Delta Air Lines (DEN). To get to Delta’s gates in Concourse A, travelers must take the airport train from Terminal East, where check-in and luggage drop are situated. Along with a variety of culinary and shopping options, the concourse has cozy seating places. It is easy to access security and transportation services at DEN, so passengers can anticipate a seamless Delta experience.