Hunting Captain America
After the Attack on Nick Fury, Captain America returned to the Triskelion reporting to Alexander Pierce. After leaving his office, Rogers was attacked on an elevator on his way down. After jumping out of the elevator and escaping the Triskelion, Jasper Sitwell ordered the remaining S.H.I.E.L.D. agents to hunt down Captain America. In order to insure his capture, he ordered the closing off of all airports in the area including BWI.