The US Air Force has different images that officially represent the military service in formal and informal settings. The Seal, Emblem, and other symbols are all trademarked for official use only. Educational use is authorized as well. Flag making companies are using the USAF Emblem to sell unauthorized cheap flags and members of the American public are buying them. If you have not read about the proliferation of the Emblem being used as the USAF flag, please read Official and Unofficial USAF Flags.
The following is meant to help you understand the various symbols of the USAF, what they mean, and how they are used.
The USAF Seal. This is the only official symbol that represents the USAF. It is for official use only. Commercial and other unauthorized use is punishable by law.
The Air Force Emblem, which contains the Coat of Arms encircled by an outer boarder that includes the words “United States Air Force” and the Department of the Air Force Seal are very similar in appearance and are often confused. As the Air Force Seal is only authorized for internal, official use only, the Air Force Emblem is an acceptable substitute for internal Air Force use and approved external commercial requests when the use of the Seal is not authorized.
DM- The USAF Seal, at the top, is not the USAF flag and that means the Emblem is not a substitute for the USAF flag and is not supposed to be a flag at all.
This, and only this is the USAF flag, the departmental color. There is no other authorized version.
The Gen. Henry H. “Hap” Arnold Army Air Corps Symbol and Army Air Force shoulder insignia. Henry Harley “Hap” Arnold was the only General Officer to hold the grades of General of the Army and General of the Air Force. Arnold was an aviation pioneer, Chief of the Army Air Corps, Commanding General of the U.S. Army Air Forces, and the only U.S. Air Force general to hold five-star rank.
The Air Force Symbol is the official symbol of the United States Air Force. Introduced in 2000 and made official in 2004, it honors the heritage of our past and represents the promise of our future. Furthermore, it retains the core elements of our Air Corps heritage, the “Arnold” wings and star with circle, and modernizes them to reflect our Air and Space Forces of today and tomorrow.
The USAF Roundel. The roundel, also referred to as the National Star Insignia, is to be used in applications (on aircraft) when camouflage is not required.