Prince Charles has unveiled a memorial to the fighter pilots, known as "the few", who won the crucial victory in the Battle of Britain 65 years ago.
Prince Charles and the Duchess of Cornwall study the sculpture
Seventy surviving pilots, and delegates from 14 countries whose citizens flew alongside British airmen, attended the ceremony on London's Embankment.
Charles said the pilots' young age made their sacrifice "even more poignant".
Between 10 July and 31 October 1940, the RAF and the German Luftwaffe fought for air supremacy over Britain.
A wreath-laying ceremony was also held at Westminster Abbey, where the prince was accompanied by the Duchess of Cornwall and Defence Secretary John Reid.
The Australian Defence Minister Robert Hill, Czech Defence Minister Jaroslova Pribylova and ambassadors from other nations that flew alongside the British pilots, were also present.
Before the unveiling, the Prince said: "Of course the pilots were so very young, many even younger than my sons are now, and for me this makes their sacrifice even more poignant.
"I do hope that today's generation, and those generations to come will be inspired by this monument and above all will be able to reflect on the self-sacrifice of those courageous men."
The prince also noted the "horrific injuries" suffered by some pilots which "remained with them for the rest of their lives".
He added: "We shall never forget that if the few had failed in their mighty struggle, the consequences for this nation would have been quite unthinkable."
FOREIGN PILOTS FIGHTING ALONGSIDE BRITAIN
Australia (32 pilots)
Newfoundland (now a province of Canada) (1)
New Zealand (127)
Rhodesia (now Zimbabwe) (3)
South Africa (25)
The £1.65m London monument was commissioned by the Battle of Britain Historical Society and funded by public subscription
Sir Winston Churchill
It is made up of two bronze friezes set in an 82ft-long granite structure, originally designed as a smoke outlet for underground trains when they were powered by steam engines.
One frieze depicts all the achievements of Fighter Command, while the other focuses on the people of London, featuring St Paul's Cathedral and an Anderson air-raid shelter.
Accompanying them is a plaque inscribed with the names of the 2,936 pilots and ground crew from Britain and 14 other countries.
The plinth beneath the relief is engraved with Sir Winston Churchill's famous phrase: "Never in the field of human conflict was so much owed by so many to so few."
Sculptor Paul Day told BBC News he had been touched deeply by stories about the battle.
Sculptor Paul Day described the statue as a 'fitting memorial'
"I've had some veterans come up to me in the last few days who have been moved by visiting the site and seeing their names.
"That was one of my first concerns - to make something that was going to be approachable and that would connect with the people that lived through this."
Mr Reid said: "It is a fitting tribute to their selfless commitment and determination that are still exemplified by our Armed Forces today, and their personal and collective sacrifices that gave the nation hope and heart at this critical time in our history."
The Chief of the Air Staff, Air Chief Marshal Sir Jock Stirrup, also said it was a fitting tribute to the "bravery of the aircrew who fought in the Battle of Britain, and to their ground crews, support staff and the many others who together won such a seminal victory against overwhelming odds".
In June 1940 France had surrendered to the Germans, while Russia and the US had not yet joined the war against Germany. Britain led the fight against Hitler's Germany.
On 15 September 1940, RAF Fighter Command claimed victory over the Luftwaffe after a day of bombing raids ended in heavy losses for Germany.
The sculpture cost £1.65m
It is widely believed that had the RAF - outnumbered four-to-one - failed to beat them off, the Germans would easily have been able to invade the UK.
Of the RAF fighter pilots, 515 were killed.
Shortly after the RAF claimed victory, Hitler postponed and then cancelled plans to invade the UK, turning his attention to the invasion of Russia.
In other events to mark the 65th anniversary of the battle, the Duke of Edinburgh has hosted a gala dinner for veterans and guests.