Photos to demonstrate differences:
A Lockheed C-5 Galaxy: Note the positioning of the "US AIR
FORCE" title, the markings on the nose to aid in-flight refueling, and the landing gear configuration View Large View Medium
Photo © Oliver Brunke
A Boeing C-17 Globemaster III: Once again, note the positioning of "US AIR
FORCE, the lack of nose markings for IFR, the landing gear configuration, winglets, and the lack of a protrusion from the topmost forward part of the tail. View Large View Medium
Photo © Jerry Search
South Carolina - too small to be its own country, too big to be a mental asylum.