Corrected entry: Anthony is always referred to as Major Nelson, although he is wearing the insignia of a Lt. Colonel.
Corrected entry: Major Healy is an astronaut - and an Army officer. In those days, astronauts had to be pilots with thousands of hours of experience in fighters and other high-performance aircraft and the Army did not (and does not) have any such aircraft, only helicopters and a few small propeller planes. Astronauts could be Air Force, Navy, or Marine Corps pilots, but not Army. In fact, according to the insignia on his uniform, Major Healy is not even in Army aviation, but the Corps of Engineers, which is responsible for bridges, roads, dams, etc.
Correction: In the 1960s the Army did not have a branch called Aviation. Officers used their original branch insignia, like Major Healey. Army Aviation branch was officially made in the 1990s. Major Healey's uniform is correct.
Correction: Tony is wearing Major rank, which is the gold leaf. Lieutenant colonel is the silver leaf.
Halfway through the first season he is wearing a silver oak leaf. They repeatedly call him Major.
The first season was in black and white. How can you tell what color it was?