Most of the large USAF
transport activity at over the decades LAX
was in support of the transportation of satellites and other defence materials built by the various vendors adjacent to LAX
and the South Bay (Northrop. TRW, Hughes, Boeing, Raytheon etc..)
The movement of such equipment was often quite a sight - depending on its importance and classified nature it could be moved often in the middle of the night under armed military escort with local streets being closed. On two occasions I recall observing ninja like clad motorcycle forces escorting tarp covered convoy of trailers on Imperial Hwy at some odd hour of the night.
A bit of cold war trivia - the areas south of LAX
were so rich in classified defense contractors, the area was a non-go area for foreign diplomats from a host of nations (esp Soviet Union), and any visits to the region required pre-notification of the State Dept which often worked with the FBI and assigned a tail.
Also satellites and experimental fighter fuselages were often only moved under the cover of darkness not to attract attention or be photographed by potentially passing satellites above.