If the carrier code box is filled in and the airline code is given, these fares are Airline Fares. If both Airlines & YY and IATA fares are given, give first priority to Airlines Fares. When choosing a fare from the origin to the destination, and there is a list of fares that vary by carrier, you need to identify the dominant carrier. If the significant carrier has no fare of its own, use the YY Fares. Airlines ' fares are further divided into: Unrestricted Normal Fares, Primary Normal Fares / Restricted Normal Fares, and Secondary Normal Fares