There are several online correspondence courses available for academy training.  One I researched was The Centerpoint Academy.I have had some ask me about such training. It is a full service Military High School Correspondence Academy.  The Academy was founded to help future candidates for military service to acquire their high school diploma, meeting a requirement for entry into the United States Military Services.

Centerpoint Academy focuses on the specific educational needs of persons striving to acquire an entrance for service or a career in the United States Military Services.  The Administration of Centerpoint Academy has been actively involved in assisting the U.S. Military Recruiting Services of the U.S. Army, U.S. Marine Corps, U.S. Navy, and U.S. Air Force.