Since World War II, the U.S. Marine Corps has had it's own air force. Although Marine pilots learned to fly in Navy training establishments, the Marines had their own units and aviation organization. This is all changing. The Navy is now putting Marine squadrons on carriers and allowing Navy and Marine aviation officers to be interchangeable in staff and command assignments. The Marines are, unofficially, not happy with this as Marine aviation was always considered very much part of the "Marine Team." Marine pilots received infantry training early in their careers and would periodically go back and serve in Marine ground units. This may change, although no announcement on this has been made yet.