Aircraft used in Ep 13
The aircraft with U.S. Air Force markings from which Charlies group deplanes supposedly in Baraki, Pakistan is a Boeing C-97 which was retired from military service in 1978.
Even if any other agency, especially a clandestine organization were to use such an aircraft it wouldn't have U.S. Air Force markings and would be prohibitively expensive to operate.
Of course, there are currently no flying survivors and the aircraft pictured is a former California Air National Guard C-97G on display Milestones of Flight Museum, Fox Field, Lancaster, California where this scene was filmed.
http://en.wikipedia.org/wiki/Boeing_C-97_Stratofreighter#mediaviewer/F ile:Milstones-c97-070919-03-16.jpg