The Duchess of Cambridge was spotted disembarking a commercial flight on Sunday as she and her two youngest children, Princess Charlotte and Prince Louis arrived in Scotland to spend their summer with the Queen at Balmoral.
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In a video shared on TikTok of the Cambridges stepping off the plane, royal fans were quick to notice the Duchess was not travelling with her husband Prince William, nor their eldest son Prince George. If we are to assume their eldest was travelling with his father, the family have technically broken a major royal travel rule - but how?
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Royal protocol is that two heirs to the throne should never fly on the same flight together so that should there be an accident, the royal lineage is protected.
It is not clear whether the Duke and Duchess strictly follow this guidance, especially this summer when it is assumed Prince George travelled to Balmoral with his father.
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Royal protocol states no two heirs can take a flight together
However, it does seem likely that Prince George will fly separately from his siblings on future trips considering he is next in line after Prince William.
Taking to social media to air their confusion after the video of Duchess Kate and her children was shared, one fan wrote: "Prince George cannot fly with his mother and siblings as he is heir to the throne."
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Agreeing, another fan penned: "Notice how George is not with the group. I thought he is next in line for the throne after William?"
It's not the first time Prince William has broken this tradition. When his son was born, the Duke and Duchess of Cambridge took him on the same flight to Australia when Prince George was just nine months old.
The royals have previously taken the same flight
Reportedly, the Queen is able to overrule this travel protocol, particularly in the instance of little children. However, once Prince George turns 12, the Queen can no longer make this call.
He and Prince William will not be allowed to fly on a plane together - with no exceptions to the rule. Who knew royal travel could get so complicated?
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