Donald Stones joined the RAF as a trainee pilot in early 1939 and learnt to fly at White Waltham aerodrome near Maidenhead. He joined 11 group Fighter Pool based at St. Athan in South Wales to fly Hurricanes on 29th December 1939. He joined 32 Squadron at Biggin Hill in 1940. Whilst posted temporarily at Gravesend, he was billeted out with a local family. On one freezing foggy day he knew he was going to spend a boring day in the Mess and he asked his Hosts if he could borrow a book and was told to pick any one he wanted. He picked one at random and put it in his great-coat pocket. Whilst having breakfast in the Mess two other officer had a look at the book sticking out of the great-coat pocket. It was entitled "Dimsie goes to School". It was a children's book and the nick name "Dimsie" stuck with him to the end of his life. He then joined 79 Squadron and was posted to Merville.in France.

On the 18th May, he was on patrol and came across a number of Messerschmitt Me 110s -German twin engine fighters. He shot one down and possibly a second but his engine was hit by cross fire and he crash landed without injury. He then shot down 2 German reconnaissance HS126 on consecutive days. He was then sent back to England with his unit as there were no mores planes fit for combat. On the 4th June 1940, he received a telegram advising him that h had been awarded a DFC for the destruction of enemy aircraft in France. He was the first 79 Squadron pilot to be so honored since WW1 and the first of Biggin Hill's Hurricane pilots to be so. His 19th birthday was on 19th June! He was presented with the decoration in the Field at Biggin Hill by the King on 27th June.

After a brief spell as an instructor, he re-joined 79 Squadron and was sent to Malta where he reported to 249 Squadron. With a colleague, he set up the Malta Night Flying Unit, flying hurricanes painted black.