With many residents employed at the expansive Newport News Shipbuilding, the joint U.S. Air Force-U.S. Army installation at Joint Base Langley–Eustis, and other military bases and suppliers, the city's economy is very connected to the military. The location on the harbor and along the James River facilitates a large boating industry which can take advantage of its many miles of waterfront. Newport News also serves as a junction between the rails and the sea with the Newport News Marine Terminals located at the East End of the city. Served by major east–west Interstate Highway 64, it is linked to other cities of Hampton Roads by the circumferential Hampton Roads Beltway, which crosses the harbor on two bridge-tunnels. Part of the Newport News/Williamsburg International Airport is in the city limits.