At an airfield on the outskirts of London, England, a precious Spitfire fighter that once flew with the Royal Canadian Air Force is taking to the skies once again.

It's one of the world's most iconic aircraft and it's being kept airborne thanks to the efforts of the Biggin Hill Heritage Hangar, the largest Spitfire restoration facility on the planet. This particular model even made an appearance in the 1969 film, "Battle of Britain."

Greg Davis, author of the book, "The Two Seat Spitfires," says the sound of the Spitfire's Merlin engine has been described as "the sound of freedom."

"There's a lump in the throat and a warm feeling that you brought back something that's so important to our history," he told The Associated Press. "And the first time these engines fire-up and the Merlin roars again and you see it taxi off to the end of the runway… It's magic."

The crew at Biggin Hill have so far fully restored six of the planes. Mechanics painstakingly piece together the original sections with handmade new components. But it's all worth the effort for pilots like Anna Walker, who says she feels a connection to history when she has the controls of the Spitfire in her hands.

"I was a great fan of the air transport auxiliary and the women pilots who used to ferry them during the war. I try to do them proud," she told The Associated Press.

The Spitfire played a key role in fight against the Nazis during the Second World War. Around 20,000 of the planes were built in Britain and used by the Royal Air Force, the RCAF and other allied air forces.

But today, only around 70 Spitfires can fly, and the value of the planes continues to soar. Back in January, one Spitfire was listed at an auction for a sky-high £4.5 million, or C$7.5 million. That plane also appeared in the "Battle of Britain" film.

"It's got this wonderful history -- this great wartime history and then all the film history after that," Richard Grace, director of The Aircraft Sales Company told The Associated Press in January.

With files from The Associated Press.