Star Alliance carrier Singapore Airlines has only ever ceased flying to one United States airport: Houston George Bush Intercontinental Airport (IAH). The airport has had a unique history with the Asian carrier, which has operated to the Texan airport through a unique fifth freedom of the air. Initially, the airline flew from Singapore Changi Airport (SIN) to Houston via Russia, before opting for a new route via the United Kingdom in 2016. The service was eventually shelved last year.