Given the question: Information: - Grounding - Die letzten Tage der Swissair ( en : Grounding - The last days of Swissair ) is a film about the collapse in 2001 of Swissair , Switzerland 's national airline , by Michael Steiner and Tobias Fueter , presented in January 2006 . Producers : Peter - Christian Fueter & Pascal Najadi . - An airline is a company that provides air transport services for traveling passengers and freight. Airlines utilize aircraft to supply these services and may form partnerships or alliances with other airlines for codeshare agreements. Generally, airline companies are recognized with an air operating certificate or license issued by a governmental aviation body. - Switzerland, officially the Swiss Confederation, is a federal republic in Europe. It consists of 26cantons, and the city of Bern is the seat of the federal authorities. The country is situated in Western-Central Europe, and is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland is a landlocked country geographically divided between the Alps, the Swiss Plateau and the Jura, spanning an area of . While the Alps occupy the greater part of the territory, the Swiss population of approximately eight million people is concentrated mostly on the plateau, where the largest cities are to be found: among them are the two global cities and economic centres Zurich and Geneva. - Swissair AG/S.A. (Schweizerische Luftverkehr-AG; : S.A. Suisse pour la Navigation Aerienne) was for many years the national airline of Switzerland. After reading the paragraphs above, we are interested in knowing the entity with which 'grounding ' exhibits the relationship of 'main subject'. Find the answer from the choices below. Choices: - alps - aviation - company - europe - navigation - switzerland - transport
The answer is:
aviation