In the United States, business aircraft may be operated under either FAR 91 as private operations for the business purposes of the owner, or under FAR 135 of the Federal Aviation Regulations as commercial operations for the business purposes of a third party. One common arrangement for operational flexibility purposes is for the aircraft's owner to operate the aircraft under FAR 91 when needed for its own purposes, and to allow a third-party charter-manager to operate it under FAR 135 when the aircraft is needed for the business purposes of third parties (such as for other entities within the corporate group of the aircraft's owner).