The inaugural departure to Liverpool's Speke Airport at 9am, was an Aer Lingus Lockheed 14 aircraft from the grass runway close to the original passenger terminal, which was still being built at that time.
With war raging throughout Europe, the airport was effectively mothballed for the next five years.
Dublin Airport's only service was to Liverpool or occasionally to Manchester's Barton Aerodrome. Aer Lingus had been operating from Baldonnel from 1936 and had moved its operations to the new Dublin Airport in January 1940.
Dublin Airport's first scheduled service to London commenced in November 1945, with a two and a half hour direct flight to Croydon Airport and air mail services were added in 1946.
Connections to other British cities and continental European destinations were added and in April 1958, Dublin Airport got its first scheduled transatlantic service to New York.
Managing director, Vincent Harrison, explains: “Dublin Airport was established to connect Ireland with the world and 75 years on it is still fulfilling that original goal.
"In the 75 years since that inaugural flight, Dublin Airport has welcomed 435 million passengers, boosting Irish trade, tourism and investment and bringing together generations of families and friends.
"Dublin Airport's route network has grown substantially in recent years and now offers customers direct services to Britain, North America, Continental Europe, the Middle East and Africa.
"This year, as we celebrate Dublin Airport's 75 birthday, we continue to expand and improve the operation to offer our customers more destinations and additional choice and flexibility, with 14 new services already announced for 2015."
To mark its 75th birthday, Dublin Airport has musical entertainment from the 1940s and 1950s in both terminals, and an exhibition charting the airport's 75 years has also been installed in Terminal 1 and will be open to the public throughout the year.
Dublin Airport will also be celebrating its birthday on social media throughout 2015, sharing photographs, memories and facts under the DUB75 hashtag.
Work at Dublin, which was originally known as Collinstown Airport, began in 1937 after the site was selected as the location for the capital's new civilian airport.
Collinstown had been a base for the British Royal Air Force before the creation of the Irish Free State in 1922, but the old military airfield had fallen into disrepair by the late 1930s.
The centre-piece of the new airport was its passenger terminal, which was designed by Desmond FitzGerald and a team of young architects, and the original terminal, which was designed to cater for up to 100,000 passengers per year, won several architectural awards.
It’s tiered design, viewing decks and balconies are reminiscent of an ocean liner, which was a common theme for airports of the 1930s, and FitzGerald's terminal was the key passenger facility at Dublin until the early 1970s and part of the original terminal is still use today as a boarding gate area.
"The designers of the old terminal should be praised for creating a wonderful modern facility that passengers enjoyed for many decades and that remains an icon of the early days of Irish commercial aviation," Harrison says.
Initially, air travel was the preserve of the wealthy. But with growing incomes and additional routes, passenger numbers increased and by 1963, Dublin's passenger numbers had exceeded one million in a single year for the first time.
In the 1950s and 1960s the airport was a destination in its own right, as people travelled out to Collinstown to see the planes and to dine in its restaurant, which was said to be one of the best in the country.
Guided tours of the airport were popular and Dublin featured regularly in postcards of the time.
Dublin Airport timeline
* 1936 - Irish Government announces plans for civilian airport at Collinstown
* 1938 - Work begins on the new terminal building
* 1940 - Dublin Airport opens with one flight per day to Liverpool
* 1945 - First Dublin Airport-London service begins to Croydon
* 1947 - KLM starts Dublin-Manchester-Amsterdam service
* 1948 - Completion of concrete runways
* 1949 - Passenger numbers reach 200,000 per year
* 1958 - First scheduled transatlantic service as passenger numbers
top 500,000 per year
* 1959 - North Terminal opens
* 1963 - Welcomes more than 1 million passengers
* 1972 - Terminal 1 opens
* 1989 - Passenger numbers reach 5 million
* 1990 - Celebrates 50th birthday
* 1997 - Welcomes more than 10 million passengers
* 2008 - Passenger numbers reach a record 23.5 million
* 2010 - Terminal 2 opens
* 2014 - Welcomes 21.7 million passengers
* 2015 - Celebrates 75th birthday