- September 12, 1919: Queen Wilhelmina awarded KLM - yet to be founded - its "Royal" designation.
- October 7, 1919: Dutch Royal Airlines for the Netherlands and its Colonies (Koninklijke Luchtvaart Maatschappij voor Nederland en Koloniën - KLM) was founded.
- October 21, 1919: The first KLM office opened on Heerengracht in The Hague.
- May 17, 1920: KLM's first pilot, Jerry Shaw, flew from London to Schiphol in a leased De Havilland DH-16.
- April 4, 1921: Following a winter hiatus, KLM resumed service with its own pilots and aircraft: the Fokker F-II and F-III.
- May 9, 1921: KLM opened its first passenger office on Leidseplein in Amsterdam.
- October 1, 1924: KLM initiated its first intercontinental flight, from Amsterdam to Batavia (Colonial Jakarta) in a Fokker F-VII.
- September, 1929: KLM started regular, scheduled service between Amsterdam to Batavia. Until the outbreak of the Second World War, this was the world's longest-distance scheduled service.
- December 1933: KLM flew Christmas and New Year's cards from Amsterdam to Batavia in a record time of just over four days in a Fokker F-XVIII Pelikaan. The mail arrived in time for Christmas.
- October 1934: The Douglas DC-2 Uiver won a "handicap" race - a flight with passengers and cargo - from London to Melbourne.
- December 1934: KLM made its first transatlantic flight, from Amsterdam to Curacao in a Fokker F-XVIII Snip.
- September 1945: KLM resumed service following the Second World War, starting with domestic flights.
- May 21, 1946: KLM initiated scheduled service between Amsterdam and New York using the Douglas DC-4 Rotterdam.
- November 1, 1958: KLM opened its Amsterdam-Tokyo service, flying over the North Pole using the Douglas DC-7 Caraïbische Zee.
- March 1960: The Jet Age began with the introduction of the Douglas DC-8.
- September 12, 1966: NLM ("Netherlands Airlines") was founded. This was later renamed NLM Cityhopper.
- April 1967: Schiphol Center went into service.
- February 1971: The Wide-body Age began with the advent of the Boeing 747-206B.
- March 1, 1971: KLM opened its headquarters in Amstelveen, south of Amsterdam.
- November 1975: KLM added the Boeing 747-306B Combi to its fleet, an important milestone for KLM cargo transport.
- March 1988: KLM took over NetherLines European Commuter service.
- June 1989: KLM introduced the Boeing 747-400, the most advanced 747 of its time.
- July 1989: KLM acquired a 20% interest in the US carrier Northwest Airlines, an important step toward the creation of a worldwide network.
- April 1, 1991: KLM merged NLM Cityhopper and NetherLines to create KLM cityhopper.
- October 1991: KLM increased its interest in charter carrier Transavia from 40% to 80%.
- December 1991: KLM introduced Flying Dutchman, making it the first airline on the European continent to create a frequent flyer loyalty program.
- January 1993: The US Department of Transportation granted KLM and Northwest Airlines antitrust immunity, allowing the two airlines to intensify their partnership.
- September 1993: KLM and Northwest Airlines started operating all their flights between the US and Europe as part of a joint venture.
- November 1993: For the first time in its history, KLM transported more than ten million passengers in a single year.
- March 1994 : KLM and Northwest Airlines introduce World Business Class, a new product on intercontinental flights.
- July 1995 : KLM introduced Boeing 767-300ER to service.
- January 1996 : KLM acquires 26% share in Kenya Airways.
- January 1998 : KLM and Malaysian Airlines System announce investigation into commercial cooperation.
- February 1998 : KLM-Northwest Airlines alliance honored with ‘Airline of the Year Award’ by influential US trade magazine Air Transport World.
- August 1998 : KLM repurchases all regular shares from the Dutch state. The state retains cumulative preference shares A and priority shares with a franchise in excess of 14%.
- November 1, 1999: KLM founded AirCares, a communication and fundraising platform supporting worthy causes and focusing on underprivileged children around the world.
- December 1999: KLM was the world's first airline to attain ISO 14001 certification for its Environmental Management System.
- Spring 2002: KLM announced the first phase of a fleet renewal program for its intercontinental aircraft - three Boeing 747-400ER freighters and eight Boeing 777-200ERs to replace the Boeing 747-300s; two more Boeing 777-200ERs to replace two MD-11s. KLM placed an order with Airbus for six A330-200s. Upon completion of the program, KLM's fleet consisted solely of Boeing 747-400s, Boeing 777-200ERs, and Airbus A330-200s.
- October 25, 2003: KLM's first Boeing 777-200R landed at Schiphol. The aircraft provides service to Cape Town, Nairobi, and New York.
- May 5, 2004: The AIR FRANCE KLM Group was born. On this day Air France redeemed the conditions of its share bid, allowing for the merger between Air France and KLM. Seven months earlier, in September 2003, the airlines had decided to join forces.
- September 2004: KLM, Northwest, and Continental join SkyTeam, an international alliance of airlines, of which Air France, Delta Air Lines, Alitalia, Korean Air, ČSA Czech Airlines, and Aeromexico were already members.
- June 2005: AIR FRANCE KLM introduced its new, combined, frequent flyer program, "Flying Blue." It was the first time in history that two European airlines had joined their loyalty programs - exclusive service packages targeting loyal customers.
- August 25, 2005: Aircraft manufacturer Airbus delivered the first of KLM's A330s.
- December 2006: KLM was the world's first airline to introduce self-service transfer kiosks at which transfer passengers at Schiphol can print out their own boarding passes, quickly and easily.
- June 2007: KLM introduced a unique partnership with the Worldwide Fund for Nature. The agreement includes hard and fast limitations to CO2 emissions and the corporate expression that, even in the airline industry, there are different and better ways of doing business. KLM views this cooperative effort as a crowning achievement to the steps it had already taken in corporate sustainability - efforts that have earned it the title of "best in class" in terms of energy efficient flight among all the major international airlines.
- March 30, 2008: The Open Skies treaty went into effect, allowing airlines to fly freely - for the first time - between Europe and the US. KLM had long been a proponent of this treaty.
- May 23, 2008: The US Department of Transportation granted antitrust immunity to KLM, Air France, Delta Air Lines, and Northwest Airlines. This will allow these airlines to make better use of the Open Skies treaty, streamlining their activities and better attuning them to customer demand.
