Turkish Airlines is the national flag carrier airline of Turkey, headquartered at the Turkish Airlines General Management Building on the grounds of Atatürk Airport in Yeşilköy, Bakırköy, Istanbul. It operates scheduled services to 41 domestic and 203 international airports in Europe, Asia, Africa, and the Americas. With 245 destinations, the airline is the fourth-largest carrier in the world by number of destinations. With Istanbul Atatürk Airport being the main base, the Turkish carrier has secondary hubs at Esenboğa International Airport, Sabiha Gökçen International Airport, and Adnan Menderes Airport. THY has been a member of the Star Alliance network since 1 April 2008. In April 2010, "TURKISH" replaced "TURKAIR" as the new call sign for Turkish Airlines.