LONDON (AP) — Prince Harry marked his 31st birthday on Tuesday at a gathering of vintage Battle of Britain aircraft honoring the pilots who helped protect the country during World War II.

Harry watched as some 40 Spitfire, Hurricane and Bristol Blenheim bombers flew in formation before dispersing to wartime airfields in the south of England.

The 75th anniversary celebration was attended by some of the surviving pilots, who are now in their 90s.

About 544 personnel from Fighter Command died during the Battle of Britain in 1940 as Hitler's Luftwaffe was repelled.

Harry, wearing a beard he grew over the summer, met with some of the veteran pilots. He briefly took the controls of a Spitfire at an event last year but plans for him to ride on one Tuesday were scrapped.