British Airways, which has flown under a series of names in its history, will celebrate its 90th anniversary today.
The airline can trace its origins back to the time Air Transport & Travel Ltd (AT&T) embarked on its first flight - from London to Paris - on 25 August 1919.
An Airco DeHavilland 4A aircraft, powered by a single Rolls-Royce engine, flew from Hounslow Heath in west London to Le Bourget in Paris in two hours 30 minutes.
The fare for what was the world's first daily international air service was 42 guineas (£44.10 in present-day money) which is the equivalent of around £1,700 today.
Prime Minister Gordon Brown paid tribute to the airline today.
He said: "British Airways has never lost the pioneering spirit and vision that saw it take to the skies with the world's first daily international flight from London to Paris on this day in 1919.
"Ninety years on, the world's most iconic airline is still proudly flying the flag and remains a great British brand. Many congratulations to all its staff - past and present, on this special day."
To mark the anniversary, precision-cut crystal company Swarovski have lent a giant bejewelled Union Flag to the airline.
The 4ft by 2ft artwork is embossed with more than 126,000 crystallised Swarovski elements and will be in the BA arrivals lounge at Heathrow's Terminal 5 until September.
AT&T later became Daimler Airways which, in turn, led to the formation of Imperial Airways in 1924.
In 1936 a separate operator British Airways Ltd was formed, starting operations from Heston in Middlesex close to the modern-day Heathrow.
In 1940 Imperial Airways and British Airways were nationalised to form BOAC (British Overseas Airways Corporation), with BEA (British European Airways) starting in 1946.
In 1974, BOAC and BEA merged to form BA which was privatised in February 1987.
BA chairman Martin Broughton said today: "Over the past nine decades, British Airways has played its part in many historic episodes.
"We provided the first air links to far-flung capitals in the days of empire, flew Winston Churchill across the Atlantic during wartime, brought Queen Elizabeth II back to Britain after the passing of George VI, repeatedly led the way with aircraft innovation and have often proudly transported home our sports teams from success overseas.
"We have a rich history supporting Britain and will carry this forward to our centenary and beyond."Reuse content