In 2018, there were 59 airlines in the United States, of which 17 are classified as major carriers with over one billion U.S. dollars in revenue. Broadly, the airlines in the U.S. can be divided into three main categories: full-service legacy carriers, low-cost carriers and regional carriers. Legacy carriers are those airlines with established interstate routes at the time of the airline industry deregulation in 1978. In the decades since, the three giant legacy carriers - Delta, American and United – have collectively merged with or acquired the majority of carriers existing prior to deregulation. Alaska Airlines and Hawaiian Airlines are the only other legacy carriers still in operation. The legacy carriers presently account for just over half of the domestic market and the majority of intercontinental flights.
Low-cost carriers emerged since deregulation and have fundamentally changed the airline industry by offering significantly cheaper fares than full-service carriers. This is achieved largely through charging extra for services like checked baggage, food and beverages, and in some cases inflight entertainment. U.S. low-cost carrier Southwest is the world’s largest, while JetBlue is in the top ten. Other U.S. low-cost carriers include Spirit, Allegiant and Frontier. Interestingly, several low-cost carriers consistently outscore the full-service carriers in for customer satisfaction.
Finally, regional carriers are those with operating revenue of below100 million U.S. dollars and provide services to communities too small to justify the presence of a mainline carrier. The regional segment differs in that while overall U.S. air travel industry has been growing, the number of regional carriers and passengers transported has been declining. High operating costs, low demand and the effects of the pilot shortage are the factors generally provided to explain this decline.