As of 2001[update], 6 US airlines (American Airlines, Continental Airlines, Delta Air Lines, Northwest Airlines, US Airways, and United Airlines) had flights that had a change of gauge. Title 14 CFR Part 258, "Disclosure of Change of Gauge Services," requires air carriers to disclose to passengers, travelling on a single flight number, if they will be required to change planes during the flight. Part 258 requires the air carriers to inform the consumer that there is a change of gauge in the itinerary before the reservation is made.[4]