oneworld (founding member, 1999)
American Airlines (AA)
Legacy / full-service network carrier · HQ Fort Worth, Texas
SkyTeam (founding member, 2000)
Delta Air Lines (DL)
Legacy / full-service network carrier · HQ Atlanta, Georgia
Star Alliance (founding member, 1997)
United Airlines (UA)
Legacy / full-service network carrier · HQ Chicago, Illinois
None (does not interline with other airlines for connecting itineraries)
Southwest Airlines (WN)
Low-cost / point-to-point carrier · HQ Dallas, Texas
None (codeshare partnerships with American Airlines on selected routes and joint ventures with British Airways and Aer Lingus on transatlantic flying)
JetBlue Airways (B6)
Hybrid low-cost / leisure-focused carrier · HQ Long Island City, New York
oneworld (joined 2021)
Alaska Airlines (AS)
Full-service carrier · HQ SeaTac, Washington
None (extensive bilateral codeshares with JAL, Korean Air, Virgin Australia, ANA, and others; group-level oneworld access via Alaska Airlines parent)
Hawaiian Airlines (HA)
Full-service carrier (focused on Hawaii) · HQ Honolulu, Hawaii
None
Frontier Airlines (F9)
Ultra-low-cost carrier (ULCC) · HQ Denver, Colorado
None
Spirit Airlines (NK)
Ultra-low-cost carrier (ULCC) · HQ Dania Beach, Florida