Hello Dan,
it depends what you mean by his "war diary".
Do you know for a fact that he wrote a diary? Or do you mean his pilot's log book? If either exist, they would probably either be in the hands of a collector or in a museum. As he was a Canadian, you might enquire of Canadian museums, both air related and local in Ontario.
He took American citizenship after the war so that's another possibility.
If you just want his record, I would refer you to page 187 of
Above the Trenches for a potted biography and list of his claims. More detail would be in the Air 76 files at the Public Record Office at Kew in London.
He wrote his Autobiography
- might be worth a search on Abebooks.com or Addall.com for a copy.
Mike