In the United States, LCCs hold above 30 percent of the domestic market. Overall, Southwest was ranked second among the leading airlines in the U.S., with a market share of 17.6 in 2019, just behind legacy carrier American Airlines. With flights to 101 destinations, Southwest transported passengers over 133 billion miles, had a capacity of around 159.8 billion available seat miles (ASMs) and reported net profits of almost 2.5 billion U.S. dollars in 2018. JetBlue Airways was ranked sixth, with a domestic market share of 5.6 percent and operating revenue streams of almost 7.7 billion U.S. dollars in 2018.
Of particular interest is the emergence of the ultra-low cost carriers (ULLCs), like Spirit Airlines, Frontier Airlines or Allegiant Air in the U.S. domestic market, all of which are benefiting from the low jet fuel prices. Based on its ultra-low cost business model, Spirit Airlines provides unbundled base fares with the option of booking other ancillary air-related products. They currently serve 76 destinations in the United States, Caribbean and Latin America. The company reported operating revenue streams of over 3.3 billion U.S. dollars from transporting passengers over more than 30 billion miles in 2018.