Prince Harry has given up his seat in a Spitfire on his 31st birthday.
He made the sacrifice to ensure a veteran and two wounded servicemen can still take part in the biggest gathering of Battle of Britain aircraft since the Second World War to mark the aerial conflict's 75th anniversary.
Around 40 Spitfires, Hurricanes and Bristol Blenheim bombers are flying in formation from Goodwood Aerodrome in West Sussex before dispersing across wartime airfields over the South of England.
The Prince was due to have a seat in one of four two-seater Spitfires taking part in the flypast but when one of the vintage aircraft developed mechanical problems, he decided to step aside to ensure the event's special guests would still get to fly.
His spokesman said he wanted to make sure that 95-year-old Tom Neil, an ex-wing commander and Battle of Britain Hurricane and Spitfire pilot, would still be able to take part.
And he wanted to ensure that a former para and an RAF corporal who won places on a Spitfire scholarship training programme were also still able to take part in the display.
Nathan Forster, a former private in the Parachute Regiment, from South Shields, Tyne and Wear, suffered severe damage to his left leg in an IED blast while on patrol in Helmand Province, Afghanistan, in 2011.
And Corporal Alan Robinson, an RAF aircraft technician, from Market Rasen, Lincolnshire, lost a leg in a motorbike accident.
The scholarship was established by the Boultbee Flight Academy and is supported by the Royal Foundation of The Duke and Duchess of Cambridge and Prince Harry's Endeavour Fund - which donates money and offers practical help to sporting and adventure challenges for wounded ex-service personnel.
Harry had been due to fly in the Spitfire PV202 piloted by John Romain, managing director of the Aircraft Restoration Company at Duxford, Cambridgeshire.
But the Prince was previously able to fly in a Spitfire when, in August last year, he met pilots who were training for today's event, and he even had the chance to take the controls.
Today's display, which has been delayed by two hours because of poor weather, is a tribute to the Second World War pilots famously dubbed "The Few" by wartime prime minister Winston Churchill for their efforts defeating the Luftwaffe.
During the summer and autumn of 1940, 544 personnel from Fighter Command died as the RAF fought in the skies above southern England to force back the threat of any invasion by Hitler.
The 75th anniversary is likely to be the last major anniversary at which the surviving members of the pivotal conflict - who are now all well into their 90s - will be fit to take part.
The event has been organised by the Boultbee Flight Academy, based in Chichester, and two of the aircraft - a Spitfire and a Hurricane - fought in the famous battle.
A royal spokesman said Harry was "incredibly honoured" to be part of the event on his birthday.
Prior to the display, Harry was stopped by a security vehicle as he attempted to cross the runway because of an incoming small aircraft.
Security staff raced up to the Prince and asked the group to stop. They duly moved aside and waited for the plane, which landed a couple of minutes later.
During the day, Harry has met the aircraft owners, pilots and engineers at Goodwood Aerodrome, and had a chance to chat with some of the few remaining Battle of Britain veterans.