Question: Which airline that has Chelyabinsk Airport as a secondary hub is based in Yekaterinburg, Russia?
Context: Chelyabinsk Airport (IATA: CEK, ICAO: USCC) is an airport in Russia located 18 km north of Chelyabinsk.  It services large airliners and can park up to 51 aircraft.  It also serves as a secondary hub for S7 Airlines and Ural Airlines. Enkor (full name is "Joint Stock Company (JSC) Enkor") was an airline based in Moscow, Russia.  It operated scheduled international passenger services and provided technical aircraft maintenance.  Its main bases were Domodedovo International Airport, Moscow, Ulan Ude Airport (UUD) and Chelyabinsk Airport (CEK).  In 2004 the airline merged with S7 which inherited their fleet of TU-154M aircraft.  The TU-134 and Yakovlev Yak-42 aircraft were retired and the TU-154B2 was sold to Kolavia. Chelyabinsk Airlines was an airline based in Chelyabinsk, Russia.  It operated trunk and regional scheduled and charter passenger flights and also leased aircraft to other operators.  It was formerly the Aeroflot Chelyabinsk Division.  Its name was often shortened to "Chelal".  From 1994 the airline operated Yakovlev 42 tri-jet airliners. Koltsovo International Airport (Russian: Аэропорт Кольцово ) (IATA: SVX, ICAO: USSS) is the international airport serving Yekaterinburg, Russia, located 16 km (10 mi) southeast of the city.  Being the largest airport in Sverdlovsk Oblast, Koltsovo also serves nearby towns such as Aramil, Sysert, and Polevskoy.  In general, the airport is responsible for serving approximately 4,290,000 people.  The airport is a hub for Ural Airlines, RusLine and Aviacon Zitotrans.  Due to its location in the center of Russia, Yekaterinburg's airport is included in the "Priority Airports" list of Russia's Federal Air Transport Agency (Rosaviatsia). Tallinn Airport (Estonian: Tallinna lennujaam , IATA: TLL, ICAO: EETN ) or Lennart Meri Tallinn Airport (Estonian: Lennart Meri Tallinna lennujaam ) is the largest airport in Estonia and serves as a hub for the national airline Nordica, as well as the secondary hub for AirBaltic and LOT Polish Airlines.  It was also the home base of the now defunct national airline Estonian Air.  Tallinn Airport is open to both domestic and international flights.  It is located 2.7 NM southeast of the centre of Tallinn on the eastern shore of Lake Ülemiste.  It was formerly known as Ülemiste Airport. Ural Airlines (Russian: Ура́льские авиали́нии , "Ural’skiye avialinii") is an airline based in Yekaterinburg, Russia, operates scheduled and chartered domestic and international flights out of Koltsovo International Airport.  In 2012, the company transported 3.5 million passengers. America West Airlines was a U.S. airline headquartered in Tempe, Arizona.  Their main hub was at Sky Harbor Airport in Phoenix, Arizona, with a secondary hub at Las Vegas McCarran International Airport in Las Vegas, Nevada.  The airline became part of the US Airways Group after it acquired the larger airline in 2005 and adopted the US Airways brand name.  America West was the second largest low-cost carrier in the U.S. after Southwest Airlines and served approximately 100 destinations in the US, Canada, and Mexico.  Service to Europe was provided through codeshare partners.  In March 2005, the airline operated a fleet of 132 aircraft, with a single maintenance base at Sky Harbor Airport in Phoenix.  Regional jet and/or turboprop feeder flights were operated on a code sharing basis by Mesa Airlines and Chautauqua Airlines as America West Express. Olympic Air S.A. (Greek: Ολυμπιακή ) is a regional airline, a subsidiary of the Greek airline carrier Aegean Airlines.  It was initially formed from the privatization of the former Greek national carrier Olympic Airlines, a company that carried the name Olympic Airways from 1957 to the beginning of the 21st century.  Olympic Air commenced limited operations on 29 September 2009, after Olympic Airlines ceased all operations, with the official full-scale opening of the company taking place two days later on 1 October 2009.  Its main hub is Athens International Airport, with Rhodes International Airport serving as secondary hub.  The airline's headquarters are in Building 57 at Athens International Airport in Spata, and its registered seat is in Koropi, Kropia, East Attica. Chelyabinsk Shagol Airport (also Bakal) is an airfield in Russia located in the northwest part of Chelyabinsk.  It was the first airport in Chelyabinsk, opened in 1938.  Since 1953, all passenger traffic is handled by Chelyabinsk Balandino Airport, and Shagol Airport is used by the local pilots' training school, the Chelyabinsk Red Banner Military Aviation Institute of Navigators.  In August 2007 it was used in military exercises of Shanghai Cooperation Organisation.  It was a military bomber training base during the Cold War and had about 35 Tupolev Tu-134 UBLs based as recently as 1995.  The airport can park over 40 aircraft.  It is also used for air shows. Chelyabinsk (Russian: Челя́бинск ; ] ) is a city and the administrative center of Chelyabinsk Oblast, Russia, located in the northeast of the oblast, 210 km south of Yekaterinburg, just to the east of the Ural Mountains, on the Miass River, on the border of Europe and Asia.  Population:  (2010 Census) ;  (2002 Census) ;  (1989 Census)
Answer: Ural Airlines