(a) The Regular Army is the component of the Army that consists of persons whose continuous service on active duty in both peace and war is contemplated by law, and of retired members of the Regular Army.
(b) The Regular Army includes -
(1) the officers and enlisted members of the Regular Army;
(2) the professors, director of admissions, and cadets of the United States Military Academy; and
(3) the retired officers and enlisted members of the Regular Army.
37 USC 101(18) states, "The term 'active duty' means full-time duty in the active service of a uniformed service, and includes full-time training duty, annual training duty, full-time National Guard duty, and attendance, while in the active service, at a school designated as a service school by law or by the Secretary concerned."
38 USC 101(b)(21) states, "The term 'active duty' means service as a cadet at the United States Military, Air Force, or Coast Guard Academy, or as a midshipman at the United States Naval Academy."
38 USC 1965(1)(d) states, "The term 'active duty' means full-time duty as a cadet or midshipman at the United States Military Academy, United States Naval Academy, United States Air Force Academy, or the United States Coast Guard Academy."
The National Defense Authorization Act for FY 2006, signed into Public Law by the President on January 6, 2006, expanded the definition of a veteran (for purposes of preference eligibility) in 5 USC 2108(1). The new definition includes individuals who served on active duty for more than 180 consecutive days, other than for training, any part of which occurred during the period beginning September 11, 2001, and ending on the date prescribed by Presidential proclamation or by law as the last day of Operation Iraqi Freedom.
Cadets at the military academies cannot count their cadet time towards military active / retired pay and allowances nor can they claim the time for years of service for retirement. It's just the way the Congress designed it even though it seems to fly in the face of the current definitions of "active duty", etc.