Written by Jack Guy, CNN

Smiling pilots crouching atop their planes. Squadrons of bombers soaring above the clouds. Crews taking a break during a training day.

These images, recently restored for a book curated by London's Imperial War Museum, provide a rare glimpse of World War II in color.

They highlight the key role of aerial battles in the 1939-45 conflict, with a focus on the pilots and planes that protected Allied airspace and carried out raids on enemy targets.

Celebrations to mark a Lancaster bomber reaching 100 missions © IWM Credit: IWM TR 1795

Published under the title "War in the Air: The Second World War in Colour," the collection of images was compiled from an archive of 11 million photos at the Imperial War Museum.

Photos show pilots celebrating a bomber that has just returned from its 100th mission, another fixing his helmet before a flight, and a group of planes preparing to take off in the North African desert.

Kittyhawk Mk IIIs prepare to take off in Tunisia in 1943 © IWM Credit: IWM TR 975

The images illustrate missions undertaken by British, Commonwealth and US air forces in Europe and the Mediterranean.

A pilot crouches on top of his plane in France in 1944 © IWM Credit: IWM FRE 7212

"Color photography was a rarity during World War II; film was scarcely available and images were expensive to print," said Ian Carter, author of the book and a senior curator at the museum.

"Each photo has been carefully optimized by IWM restorers to bring back color accuracy and detail which over the years have faded from both paper and memory."

Pilots relax during a training camp in Florida in 1941 © IWM Credit: IWM TR 89

The book is one of a number of color photography collections released by the museum, which also published "The Second World War in Colour" in 2017.

Air force personnel pose at a flying school in Southern Rhodesia in 1943 © IWM Credit: IWM TR 1263

In November 2018, the UK's Press Association agency released a selection of colorized images to mark the 100th anniversary of the end of WW1.

Photographers captured a number of emotional scenes after armistice was declared, including a shot of the Victory Parade in London and the burial of the Unknown Warrior at a memorial service in the British capital in 1920.

The images were released as part of a number of events to commemorate the end of the war, in which around 8,500,000 people died and more than 21,000,000 were wounded.