The airline has been granted special permission to fly over The Mall at 1,000ft during the athlete’s parade at 3.41pm this afternoon.
The flame-coloured Firefly aircraft, which was used to bring the Olympic flame to the UK, will display a special ‘thank you’ message spanning 13 metres on its underbelly.
On the ground, British Airways ambassadors will give message boards and pens to 10,000 fans to write their own celebratory messages during the procession.
Keith Williams, chief executive of British Airways, said the Games has been "a glorious time for London" and the UK.
"Everyone involved has done an outstanding job to show this country at its absolute best. Our fly-past is a special tribute to all of them," he said.
During the Games, British Airways hosted Park Live at the Olympic Park, where 700,000 spectators watched the action on its giant LED screens, and saw athletes interviewed on the BA stage.
Locog Chair Seb Coe said: "I'm delighted that British Airways are going to be supporting the athlete’s parade. When Firefly goes past The Mall, make sure you all look skywards."
Before the Games began, the airline placed a giant image of gold medallist Jessica Ennis and wheelchair racer Shelly Woods on the flightpath to Heathrow for thousands of incoming passengers to see.
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