In this Jan. 30, 2017 photo, ROAM Fitness CEO Cynthia Sandall poses inside the soon-to-be-open ROAM Fitness gym at Baltimore-Washington International Thurgood Marshall Airport in Linthicum, Md. Working out while waiting for your flight will soon be … an option at BWI, where the only gym at a U.S. airport past security will open this week, with plans for 20 more at airports by 2020.