Kuban Airlines (Krasnodar) has stopped all operations on December 11 following a bankruptcy filing. The carrier owned by Russian oligarch Oleg Deripaska already had been in financial difficulties for some time accumulating approximately $300 million USD in debt and has also not been able to meet a new requirement by the Russian civil aviation authority Rosaviatsia to operate at least eight aircraft to retain its air operator certificate. Kuban had been merged with low-cost carrier Sky Express (Russian Federation) (Moscow Vnukovo) back in November 2011 and most recently has operated a fleet of three A319-100s, two B737-300s and two B737-500s on domestic routes from Krasnodar and Vnukovo and international flights from Krasnodar to Istanbul Atatürk, Tel Aviv Ben Gurion and Yerevan.