The strict Royal ban young Prince George will have to follow - and it also applied to Prince William

There are a number of rules that members of the Royal Family have to stick to. These include getting permission to marry and never giving an autograph.

But there is one particular protocol which will soon impact Prince George - and it's also one his dad Prince William had to follow. There is an important Royal custom intended to secure the future of the monarchy.

It restricts who can travel together on the same plane. Prince William - who is heir to the throne - is currently allowed to fly with his three children Prine George, Princess Charlotte and Prince Louis.

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But this rule will change in the coming years, Mirror reports. Speaking on HELLO Magazine's 'A Right Royal Podcast', King Charles' former pilot Graham Laurie opened up about the rule.

He recalled how it affected Prince William when he turned 12 in 1994. He said: "Interestingly, we flew all four: the Prince, the Princess, Prince William and Prince Harry, up until Prince William was 12 years old.

"After that, he had to have a separate aircraft and we could only fly all four together when they were young with the written permission of Her Majesty. When William became 12, he would fly normally in a 125 from Northolt and we would fly the 146 out with the other three on."

George will celebrate his 12th birthday in July next year. It could be that Prince George will then have to fly separately from his dad.

But it is not yet known if he will continue to travel with his mother Catherine, Princess of Wales and his siblings while his father uses a different plane or if the second-in-line to the throne will fly solo.

The unique restriction is in place to protect the heirs to the throne. While the rule can be broken with the monarch's permission, it is discouraged.

This is because the future of the monarchy would be immediately unstable if there was a crash. Three royals have previously lost their lives in air accidents.

Prince Philip 's sister Princess Cecile died in a crash in 1937, the late Queen's uncle Prince George, Duke of Kent died in 1942 and her cousin Prince William of Gloucester died while competing in an air show in 1972.