There is the First Cavalry Division (Big yellow patch with a horse on it). This division is essentially a mechanized army division that contains infantry, tanks, howitzers, and yes helicopters. If you are thinking air cav in terms of the movie Apocalypse Now, those air assault missions are performed by light infantry brigades in partnership with division aviation assets. Traditionally the 101st Airborne division performed these missions as the only "air assault" division. In today's military cavalry units typically perform reconnaissance missions to provide intelligence for the brigades they support. However, some infantry or armor battalions have traditionally been named cavalry, but they are just armor or infantry battalions. Confused? Yes it is confusing. If you want to fly helicopters then you want to try to branch aviation. Some aviation assignments will be with units that have reconnaissance missions (cavalry). If you want to go to battle by jumping out of a helicopter than branch infantry and look to get assigned to a light infantry brigade. If you want to be a cavalry scout, then branch armor and look for assignment in a cavalry squadron. To confuse you even further, you can branch infantry, go to an infantry battalion and after duty as a line platoon leader, look to take charge of the scout platoon. Hope that clears some things up (-: