The C-21A is a military variant of the Learjet 35A business jet.  It is a twin turbofan engine aircraft for cargo and passenger airlift and is also capable of transporting litters during medical evacuations.  

In April 1984, the delivery of the C-21A fleet began and was completed in October 1985 for deployment.  On April 1, 1997, all continental US-based C-21s were realigned under Air Mobility Command, with the 375th Airlift Wing at Scott Air Force Base, Ill. as the lead command.  C-21s stationed outside the continental United States are assigned to theater commanders.

The C-21A has a maximum speed of 530 mph and a maximum range of 2,306 miles.  It has a crew of two, a pilot and a co-pilot.  The C-21A has a capacity of carrying eight passengers.  The aircraft is equipped with an automatic navigation system and four cathode ray tubes display for enhanced pilot crew efficiency.

There are 38 C-21As in active duty with the Air Force.