He is probably confused because some Air National Guard units are co-located with Army Guard unit. McEntire ANG base in South Carolina is that way: it has Army National Guard AH-64's, H-60's and Air National Guard F-16's.
However, this is probably what you want to see, beginning with the birth of the Air Force and the National Security Act of 1947.
When the Army and the Air Force became separate services after World War Two, one of the most contentious issues was defining a clear postwar identity for Army aviation. Although the institutional separation was authorized by the National Security Act in 1947 and the services agreed to a formal enumeration of their respective functions in the 1948 Key West Agreement, ten years later the Defense Department was still revisiting aviation in an attempt to clarify the Army's role.
The general thrust of departmental policy was to assign almost all missions for which fixed-wing aircraft were best suited to the Air Force, while encouraging Army aviators to rely on rotary-wing systems to accomplish the remaining missions. In 1957, Defense Secretary Charles Wilson directed that no Army fixed-wing aircraft could exceed an empty weight of 5,000 pounds, while the service's helicopters could weigh up to ten tons. Not surprisingly, Army aviation came to consist almost entirely of rotary-wing assets, a trend confirmed by the operational demands of the Vietnam War. By the late 1970s the Army had accumulated an inventory of 8,000 helicopters, the biggest and most capable such force ever assembled.
