In 1919, a young aviator lieutenant named Albert Plesman sponsored the ELTA aviation exhibition in Amsterdam. Attendance at the exhibition was over half a million, and after it closed, several Dutch commercial interests intended to establish a Dutch airline, which Plesman was nominated to head.[10] In September 1919, Queen Wilhelmina awarded the yet-to-be-founded KLM its "Royal" ("Koninklijke") predicate.[11] On 7 October 1919, eight Dutch businessmen, including Frits Fentener van Vlissingen, founded KLM as one of the first commercial airline companies. Plesman became its first administrator and director.[10]

The first KLM flight took place on 17 May 1920. KLM's first pilot, Jerry Shaw, flew from Croydon Airport, London, to Amsterdam.[11] The flight was flown using a leased Aircraft Transport and Travel De Haviland DH-16,[11] registration G-EALU, which was carrying two British journalists and some newspapers. In 1920, KLM carried 440 passengers and 22 tons of freight. In April 1921, after a winter hiatus, KLM resumed its services using its pilots, and Fokker F.II and Fokker F.III aircraft.[11] In 1921, KLM started scheduled services.

KLM Fokker F-XVIII departing from the Dutch East Indies, 1932

KLM's first intercontinental experimental flight took off on 1 October 1924.[11] The final destination was Jakarta (then called 'Batavia'), Java, in the Dutch East Indies; the flight used a Fokker F.VII[11] with registration H-NACC and was piloted by Van der Hoop.[12] In 1927, Baltimore millionaire Van Lear Black, who had heard about the 1924 flight, chartered H-NADP to do the same flight, which departed June 15 and went successfully (16 days), and flew back to much rejoicing. This inspired KLM to make a second test flight, which left on October 1, returning successfully with much experience gained.[13] In September 1929, regular scheduled services between Amsterdam and Batavia commenced. Until the outbreak of the Second World War in 1939, this was the world's longest-distance scheduled service by airplane.[11] By 1926, it was offering flights to Amsterdam, Rotterdam, Brussels, Paris, London, Bremen, Copenhagen, and Malmö, using primarily Fokker F.II and Fokker F.III aircraft.[14]