The painting Dangerous Moonlight. Photo / Doug Sherring
That success led to London newspapers dubbing him "Lone Wolf". New Zealand artist Ron Fulstow later depicted the downing of the plane in his painting Dangerous Moonlight.
Sweetman's grandson, Michael Sweetman, said King George also handed his grandfather a cigar.
"He didn't know quite what to do with it. It was a Pall Mall unfiltered, so he popped it in his pocket and kept it."
Michael Sweetman's proudest moment came when he attended a recent air force event and was pulled aside by one of his grandfather's fellow servicemen.
"He said to me, 'Michael, do you realise how many lives your Grandad saved?' I was so proud. He was so modest and always spoke of being a survivor, not a hero."
Sweetman also earned the nickname "Buzz Bomb King" because he shot down 11 flying bombs. He is survived by his wife of 66 years, Gwen Sweetman, his five sons, grandchildren and great-grandchildren.