An airline alliance is a partnership between multiple airlines that work together to provide better services to their customers. These alliances allow airlines to share resources, such as airport lounges and flight schedules, making it easier for passengers to connect between different airlines. There are three major global alliances: Star Alliance, SkyTeam, and Oneworld. By joining an alliance, airlines can expand their network without having to operate additional flights, which helps them offer more destinations and benefits, such as earning frequent flyer miles across member airlines.