For Reagan National Airport passengers who have suffered the indignity of Gate 35X — the jockeying for position in a crowded room with limited seating followed by more jockeying for the shuttle to a plane — relief is coming. Officials expect to open a new concourse in 2021 that will replace the airport’s long-standing practice of busing travelers to their planes.

The $1­ billion program, dubbed Project Journey has two parts: the new concourse and an expanded security screening area. It is being paid for in part by fees collected from airline passengers when they buy their tickets.