Midfield Concourse A and B Ramp at Washington DC Dulles are home to all airlines except United and American. This modern and airy concourse opened in 1998. The A Concourse consists of a permanent ground level set of gates designed for small planes such as regional jets and some former B concourse gates. The B Concourse is the first of the permanent elevated midfield concourses. Originally constructed in 1998, the B concourse contained 20 gates. In 2003, 4 additional gates were added to concourse B, followed by a 15-gate expansion in 2008.It is connected to the main terminal by an underground walkway in addition to the AeroTrain as part of the D-2 expansion. JetBlue is the #1 carrier (and Dulles’ #2 overall) on the B/C concourse. For a short-time, the A concourse was home of locally based Indepence Air.