Spitfire and Hurricane in Battle of Britain flypast
A Spitfire and a Hurricane have taken part in a flypast to mark the 70th anniversary of the Battle of Britain.
It was watched by Prince Charles, Prince William and Prime Minister David Cameron, who all attended a service at Westminster Abbey.
The 1940 battle saw RAF pilots repelling a German bid for air superiority, making an invasion of the UK impossible.
Prince Charles said the veterans always brought a "tear to his eye".
The Westminster Abbey service was attended by veterans of the Battle of Britain and representatives of the Ministry of Defence.
An RAF chaplain spoke of the pilots' "bravery and sacrifice" for freedom.
As well as commemorating the achievements of those who fought in the 1940s, this year's service celebrated the work of the men and women currently serving in the Royal Air Force.
The Prince of Wales is patron of the Battle of Britain Fighter Association, and his son, Prince William, has just graduated as an RAF helicopter pilot.
Following the thanksgiving service, Prince Charles said: "I always find it so moving, this particular service each year, it always brings a tear to my eye particularly in the way the wonderful veterans marched up the aisle.
"There's something very special about it. Of course we owe an enormous debt to them, it makes one feel very humble."
The Prince said it was "absolutely crucial" that the country continued to remember their sacrifice, and that the example set by veterans was important to follow today.
"We can learn an awful lot from their unbelievable selfless service and their self-discipline and, above all, their sense of duty. We see it now, of course, in Afghanistan and previously in Iraq - people of this land are truly remarkable.
"I can never get over how wonderful they are, this country does produce staggeringly special people."
The flypast also saw RAF Typhoon fighter jets fly over central London.
RAF Chaplain in Chief Raymond Pentland said at the ceremony: "Seventy years ago a generation of young men took to the skies and their bravery and sacrifice won our freedom.
"Today we salute the few and give thanks for their bravery, sacrifice and our freedom."
RAF fighter pilot Flt Lt Jonathan Davy, 44, said the Battle of Britain inspired him to join the Air Force.
Speaking before the service, the Iraq veteran said the nation owed a huge debt of gratitude to everyone involved in it.
He explained: "It's a huge, huge legacy to live up to, as a kid growing up in the 1970s and 1980s there were so many Battle of Britain films and RAF air shows it was something I had aspired to ever since I was a small boy."
Sir Stephen Dalton, Chief of Air Staff, said winning the Battle of Britain was vital to the overall outcome of the war.
Speaking outside Westminster Abbey he said: "Unless we had control of the skies over Britain we could not build up the forces ready to liberate Europe later on.
"That is entirely relevant today. Without the freedom of the skies in Afghanistan there would need to be 10 times the number of soldiers and marines on the ground to achieve the same effect."
Other commemorations for the 70th anniversary have been held this year, including one on 20 August to mark the date when wartime Prime Minister Winston Churchill said of the service personnel: "Never in the field of human conflict was so much owed by so many to so few".
The Battle of Britain began on 10 July 1940 and ended on 31 October when the Luftwaffe were pushed back by the determination and preparedness of the RAF.
More than 2,900 British, Commonwealth and Allied aircrew took part.
At least 23,000 civilians were killed during the WWII battle, the first major one to be fought entirely in the air.