Czech Airlines j.s.c. (abbreviation: ČSA, Czech: České Aerolinie, a.s.) is the flag carrier of Czechia. Its head office is on the grounds of 6th district Prague, Vokovice. The airline's hub is at Václav Havel Airport Prague. The company operates mainly scheduled flights.
The airline runs a frequent flyer programme called "OK Plus" in reference to the airline's International Air Transport Association designation, as well as the term of approval; OK also featured prominently in its previous livery, and is the prefix for the Czech Republic on aircraft registrations. It is a member of the SkyTeam alliance. Privately owned Czech airline company Smartwings owns 97.74% of the airline, with the remaining 2.26% owned by insurance company Česká Pojišťovna.
In summer season, ČSA flies to 50 destinations in Asia and Europe. Czech Airlines carried 2.26 million passengers in 2016, which was a 13% increase compared to 2015. Czech Airlines Technics is responsible for aircraft maintenance.
ČSA is the fifth oldest still operating airline in the world, after Dutch KLM (1919), Colombian Avianca (1919), Australian Qantas (1920), and Soviet Aeroflot (1923). It was the first airline in the world to fly regular jet-only routes.