Question: An example of a hidden asset is a frequent flier program that was chosen for a combined airline in what year?
Context: SkyMiles is the frequent-flyer program of Delta Air Lines that offers points (or "miles") to passengers traveling on most fare types, as well as to consumers who utilize Delta co-branded credit cards, which accumulate towards free awards such as airline tickets, business and first class upgrades, and luxury products.  Created in 1981 as the "Delta Air Lines Frequent Flyer Program"; its name was changed to SkyMiles in 1995.  Delta claims that it is the only major U.S. airline without mileage expiration, so travelers can redeem awards at their leisure.  The airline also has a separate SkyBonus program that provides small to mid-sized business owners with a way to earn points for trips taken by employees, good towards free flights, upgrades, Silver Medallion status and other travel awards. Flooz.com was a dot-com venture, now defunct, based in New York City that went online in February 1999, promoted by comic actress Whoopi Goldberg in a series of television advertisements.  Started by iVillage co-founder Robert Levitan, the company attempted to establish a currency unique to Internet merchants, somewhat similar in concept to airline frequent flier programs or grocery store stamp books.  The name "flooz" was based upon the Arabic word for money, فلوس, "fuloos".  Users accumulated flooz credits either as a promotional bonus given away by some internet businesses or purchased directly from flooz.com which then could be redeemed for merchandise at a variety of participating online stores.  Adoption of flooz by both merchants and customers proved limited, and it never established itself as a widely recognized medium of exchange, which hindered both its usefulness and appeal. Virgin America Inc. is an American airline that was founded in 2004 and began operations in 2007.  Headquartered in Burlingame, California in the San Francisco Bay Area, with San Francisco International Airport as its main hub, Virgin America is a brand that was created by the British Virgin Group as an American counterpart to the corporation's other airlines.  The airline flies between major metropolitan cities on the Eastern and West Coast seaboards.  Virgin America's frequent flyer program Elevate provides award flights and other benefits to frequent fliers. Qualiflyer was a frequent flyer program, created in April 1992 by Austrian Airlines, Crossair and Swissair.  When Swissair began acquiring stakes in other European airlines in 1998, Qualiflyer was extended to become their frequent flyer programs as well.  This spawned the alliance known as The Qualiflyer Group.  With the failure of Swissair in 2002, the group dissolved along with the program and a company was formed to give each former member airline an individual frequent-flyer program. In finance, a hidden asset is an asset that is not shown on a balance sheet.  An example of such an asset is the US $15 billion that United Airlines' frequent flyer program, MileagePlus, was estimated to be worth when it filed for Chapter 11 bankruptcy. Ripple is a real-time gross settlement system (RTGS), currency exchange and remittance network by Ripple.  Also called the Ripple Transaction Protocol (RTXP) or Ripple protocol, it is built upon a distributed open source Internet protocol, consensus ledger and native currency called XRP (ripples).  Released in 2012, Ripple purports to enable "secure, instant and nearly free global financial transactions of any size with no chargebacks."  It supports tokens representing fiat currency, cryptocurrency, commodity or any other unit of value such as frequent flier miles or mobile minutes.  At its core, Ripple is based around a shared, public database or ledger, which uses a consensus process that allows for payments, exchanges and remittance in a distributed process. MileagePlus is the loyalty program of United Airlines and Aeromar that offers rewards to passengers traveling on certain types of tickets.  Following the 2011 merger agreement between United Airlines and Continental Airlines, United Mileage Plus was chosen to be the frequent flyer program for the combined airline.  The program was subsequently renamed to MileagePlus, and maintains its relationship with its Star Alliance partners, as well as other airline and travel enterprise agreements. In the airline industry, ancillary revenue is revenue from non-ticket sources, such as baggage fees and on-board food and services, and has become an important financial component for low-cost carriers (LCCs) in Europe, North America and other global regions.  Ancillary revenue has been defined as, “Revenue beyond the sale of tickets that are generated by direct sales to passengers, or indirectly as a part of the travel experience.”  Ancillary revenue has been further defined to include these categories: à la carte features, commission-based products, and frequent flier activities. Kathie Sarachild, born Kathie Amatniek in 1943, is an American feminist writer and campaigner.  In 1968 she took the last name Sarachild (after her mother Sara), coined the phrase "Sisterhood is Powerful" in a flier she wrote for the keynote speech she gave for New York Radical Women's first public action at the convocation of the Jeannette Rankin Brigade, was one of four women who held the Women's Liberation banner at the Miss America protest, and had her paper "A Program for Radical Feminist Consciousness-Raising" presented at the First National Women's Liberation Conference outside Chicago on November 27, 1968 (it was later published in "Notes from the Second Year" in 1970.)  She was a member of New York Radical Women.  In February 1969 she led Redstockings in their disruption of the New York State Abortion Reform Hearing, at which women first demanded to testify about their own abortions.) Club Premier is a loyalty program based in Mexico, originally the frequent flyer program of Aeroméxico, the Mexican airline, now spun off and operated by PLM, which is 51% owned by Aeroméxico and 49% by AIMIA, the Montreal-based loyalty company with its origins as the frequent flyer program of Air Canada.
Answer: 2011