The airline industry originated in 1903 and has faced many changes since then. Major US airlines include American Airlines, United Airlines, and Delta Airlines. American Airlines has the largest market share at 14.8%, while United and Delta have market shares of 10.8% and 15.8% respectively. The industry faces challenges from factors like oil prices, mergers and acquisitions, and competition from low-cost carriers like Southwest Airlines. Airlines compete based on service, ticket prices, and frequent flyer mileage programs.