is turkish airlines a member of the star alliance
Yes, from December 2006.
2008–2010: Second decade of operations
On 1 April 2008, Turkish Airlines joined the alliance after a 15-month integration process beginning in December 2006, becoming its 20th member. EgyptAir, Egypt's national airline
UNANSWERABLE Yes, on 1 April 2008, Turkish Airlines joined the alliance. Yes, it joined on 1 April 2008.
Star Alliance Star Alliance
2008–2010: Second decade of operations 2008–2010: Second decade of operations
On 1 April 2008, Turkish Airlines joined the alliance after a 15-month integration process beginning in December 2006, becoming its 20th member.  On 1 April 2008, Turkish Airlines joined the alliance after a 15-month integration process beginning in December 2006, becoming its 20th member. EgyptAir, Eg
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Star Alliance [SEP] 2008–2010: Second decade of operations
On 1 April 2008, Turkish Airlines joined the alliance after a 15-month integration process beginning in December 2006, becoming its 20th member. EgyptAir, Egypt's national airline and Star Alliance's second African carrier, joined on 11 July 2008. On 27 October 2009, Continental Airlines became the 25th member of Star Alliance after leaving SkyTeam three days earlier. According to alliance CEO Jaan Albrecht, "Bringing Continental Airlines into Star Alliance has been a truly unique experience. This is the first time an airline has moved directly from one alliance to another and I would like to thank all those involved in ensuring a smooth switch".