Smartwings, a.s. (formerly Travel Service, a.s.) is a low-cost leisure Czech airline, with its head office on the property of Václav Havel Airport Prague in Ruzyně, 6th district, Prague. It is the biggest airline in the Czech Republic and it operates scheduled and chartered flights, mainly to leisure destinations, and also wet and dry leases its aircraft to other airlines. It also owns 30% of Czech Airlines, and has subsidiaries in Poland, Hungary and Slovakia.