Ryanair is an Irish low-cost carrier established in 1984 as Danren Enterprises. It was soon renamed Ryanair after one of the founders, Tony Ryan. Together with Ryanair UK, Ryanair Sun and Lauda it belongs to the Ryanair Holdings. It is the world's 1st largest airline by the number of routes served and the 5th by the number of passengers carried. Ryanair is present in as many as 37 countries, operates over 2,000 flights a day and flies over 130 million customers a year. In 2017, it became the first European airline to have carried over 1 billion passengers. It has a sister airline named Ryanair Sun which is based in Warsaw, Poland. It initially served charter flights but soon it started to operate scheduled flights on behalf of Ryanair.