Spitfire trio line up for takeoff at Biggin Hill, part of  the 75th anniversary of the “Hardest Day” in the Battle of Britain.

Spitfire trio line up for takeoff at Biggin Hill, part of the 75th anniversary of the “Hardest Day” in the Battle of Britain.

Spitfire trio line up for takeoff at Biggin Hill, part of  the 75th anniversary of the “Hardest Day” in the Battle of Britain.

Spitfire trio line up for takeoff at Biggin Hill, part of the 75th anniversary of the “Hardest Day” in the Battle of Britain.