The Vietnam War era jet fighter bomber built by McDonell, the F-4E 'Phantom II' is on display with it's longer 'E' nose packing a 20mm cannon. Saturday 8/19/1989, at the old Hector Airport terminal.

Variants for the U.S. Air Force. F-4E introduced an internal 20mm M61A1 'Vulcan' 6-barrel Gatling cannon, with 640 rounds. The F-4D and E were the most numerously built, widely exported, and also extensively used under the Semi Automatic Ground Environment (SAGE) U.S. air defense system. -wiki