Swissair AG/S.A. (German: Schweizerische Luftverkehr-AG; French: S.A. Suisse pour la Navigation Aérienne) was the national airline of Switzerland between its founding in 1931 and bankruptcy in 2002.

It was formed from a merger between Balair and Ad Astra Aero (To the Stars). For most of its 71 years, Swissair was one of the major international airlines and known as the "Flying Bank" due to its financial stability, causing it to be regarded as a Swiss national symbol and icon. It was headquartered at Zurich Airport, Kloten.

In 1997 the Swissair Group was renamed SAirGroup (although it was again renamed Swissair Group in 2001), with four subdivisions: SAirlines (to which Swissair, regional subsidiaries Crossair and Balair, and leasing subsidiary FlightLease belonged), SAirServices, SAirLogistics, and SAirRelations.

By the late 1990s, Swissair was burdened by over-expansion as a result of the controversial "Hunter Strategy". The crash of Swissair Flight 111 in 1998, which killed all 229 people on board, generated a costly lawsuit and negative publicity for the airline. After the economic downturn following the September 11 attacks, Swissair's assets dramatically lost value, grounding the already-troubled airline in October 2001. The airline was later revived and kept alive until 31 March 2002 by the Swiss Federal government. The final Swissair flight landed in Zürich on 1 April 2002.

On 1 April 2002 former regional subsidiary Crossair renamed itself Swiss International Air Lines and took over most of Swissair's routes, planes and staff. Today, Swissair Group still exists and is in the process of being liquidated. Swiss International Air Lines was taken over by the German airline Lufthansa in 2005.