A Harrier jets hangar, a square platform and retractable roof for vertical take-off, there's an upper level with catwalk around until near the jet's cockpit, and some boxes and equipment scrattered around. Its design is similiar to Antarctic Base's Hangar.
The hangar is accessed from both Alfred Ashford and Chris Redfield by using a Halberd to unlock the door to it from the passage under the tank. There were 2 jets seen, the first one was used by Alfred to chase after Claire and Steve who were aboard a C-130 Hercules. A second jet was used by Chris at a later time, to look for his sister in the Antarctic Base.