Miscellaneous Charge Orders (MCOs) An MCO is an airline transaction for a non-ticket purchase, such as an insurance payment or an excess baggage fee. An MCO must be a separate airline transaction; do not include MCO information and flight leg information in the same transaction. Include the following values in an MCO request: ■ airline_leg0_originating_airport_code=XAA ■ airline_leg0_destination=XAO Do not include any other fields for travel legs in an MCO request: ■ Do not include any other fields for leg 0. ■ Do not include any fields for legs 1, 2, or 3.