An aircraft design is defined in and approved by the issuance of a "Type Certificate" which is normally issued by a civil aviation authority to a manufacturer when the design is found to comply with all relevant design requirements.  The design is then manufactured in accordance with the airplane configuration and is defined by this certificate.

Once manufactured, the airplane is delivered to an operator to begin commercial service.  In the Operational phase, the airplane is operated by an airline in accordance with the operational requirements specified by the country responsible for overseeing that operator's activity. These operational requirements usually include all ground and flight operations, including the training and certification of the personnel conducting these operations.

As the airplane continues to be operated, maintenance is performed which is intended to keep the airplane in an airworthy condition. Repair may be necessary in order to correct damage or other events that might have occurred. Alterations may be also desired which change the configuration of the original design.