St. Louis, MO STL to Boston, MA BOS flight with United

PSA Airlines is an American regional airline and a wholly-owned subsidiary of the American Airlines Group, operating exclusively on behalf of American Airlines under the American Eagle brand. Headquartered in Charlotte, North Carolina, PSA Airlines operates over 800 daily flights to nearly 100 destinations across the United States. The airline maintains an all-jet fleet consisting of Bombardier CRJ700 and CRJ900 regional aircraft. With a team of over 5,000 employees, PSA Airlines plays a significant role in connecting smaller cities to major hubs within American Airlines' network.

Alaska Airlines, headquartered in SeaTac, Washington, is a major U.S. airline and the fifth-largest in North America by scheduled passengers carried as of 2024. Along with its regional partners, Horizon Air and SkyWest Airlines, Alaska Airlines operates a route network primarily connecting cities along the West Coast of the United States, including Alaska and Hawaii, to over 100 destinations in the contiguous U.S., the Bahamas, Belize, Canada, Costa Rica, Guatemala, and Mexico. The airline is a member of the Oneworld alliance, offering passengers access to a broad global network. Alaska Airlines is known for its customer service and loyalty program, Mileage Plan, and offers First Class, Premium Class, and Main Cabin seating options. The airline's primary hub is Seattle-Tacoma International Airport. In 2024, its parent company, Alaska Air Group, acquired Hawaiian Airlines.

Republic Airways is a major regional airline in the United States, operating as a subsidiary of Republic Airways Holdings. It provides scheduled passenger service for American Airlines (as American Eagle), Delta Air Lines (as Delta Connection), and United Airlines (as United Express) using a fleet of Embraer 170 and 175 regional jets. Headquartered in Indianapolis, Indiana, Republic Airways operates over 900 daily flights to more than 80 cities across the U.S. and Canada. The company is known for its large fleet of Embraer E-Jets and its state-of-the-art training facilities. In April 2025, Republic Airways Holdings announced its acquisition of Mesa Air Group, which is expected to create the second-largest regional carrier in the U.S.