Franciszek Kornicki, 100, admitted he was “a little dazed” by the news that he was ahead of British fighter aces including Sir Douglas Bader in the People’s Spitfire Poll – and leading by more than 300,000 votes.
Museum staff launched the online poll to celebrate the 100th anniversary of the RAF next year.
Sergeant Kornicki, who is the last surviving Second World War Polish squadron commander, soared into the lead after a campaign in the Polish media.
The pilot said: “I’m very surprised and even a little dazed by this news. I was only one of many and I knew quite a lot of better flyers than me.”
Kornicki, like hundreds of other Polish pilots, retreated across Europe after the Nazis invaded in 1939.
He arrived in Britain in 1940 and joined 303 Squadron, which was the highest-scoring fighter unit during the Battle of Britain.
Less than three years later, aged 26, he was the youngest squadron commander in the Polish Air Force.
He received Poland’s highest military decoration after leading British bombers over France and ordering an attack on Nazi planes flying towards them.
Describing the reaction after four German fighters were shot down, Mr Kornicki said: “It may not have done much to advance the war effort but it was fantastic for morale”.
Mr Kornicki, who lives in a care home in Findon, West Sussex, spoke of the close camaraderie between British and Polish pilots.
He said: “When I was commanding 317 Squadron, which had its base in London’s Northolt, pilots often sat at the Orchard Hotel bar.
“Everyone, not only Polish and British airmen but also local residents, stayed there until the late hours.
“I remember that the owner of the bar valued us and took care of the youngest and poorest aviators.
“When he saw that one of them ordered only half a pint of beer, he sent him over a double at his own expense.”
Sir Douglas Bader, who is second in the poll with almost 6,000 votes, led 242 Squadron during the Battle of Britain and spent three years as a PoW after being shot down over France.
Museum curator Peter Devitt said: “We are astonished how successful the poll has been.”
Voting closes on Sunday and a lifesize cut-out of the winner will stand next to a Spitfire in the museum’s centenary exhibition next year.