Fly the Friendly Skies

A military transport plane, from one of my uncle's slides from the 1950s. Note the family in civilian attire approaching the nose of the plane, and the jet engine on the yellow test rig in the background.

The plane appears to be a Fairchild C-119 Flying Boxcar. The nose marking on the plane reads "6614 ATS", the number on the nosewheel door is "8048" (possibly identifying it as number 51-8048). This census site doesn't include a plane with "8048" as a number, so it's not one of the surviving copies apparently.

If you look carefully, it appears that the plane has its tail doors open.