This tradition was also followed by Prince William, who, upon turning 12, had to begin flying separately from his father, Prince Charles, and his brother, Prince Harry.
Explained by a Royal Pilot
Graham Laurie, former pilot to King Charles, explained the details of this travel protocol in an interview with OK! Magazine:
“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,” Laurie recalled.
“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.”

A History of Tragedy in Royal Aviation
While this rule is not formally written into law, it is a deeply respected safety measure within the royal household, shaped in part by historical tragedies.
In 1937, Prince Philip’s sister, Princess Cecilie, died in a plane crash. Just five years later, Queen Elizabeth II’s uncle, Prince George, was also killed in an aviation accident. Another royal, Prince William of Gloucester—cousin to the late Queen—died in a similar crash in 1972.
These incidents serve as somber reminders of why such precautions are taken seriously, even if unwritten.
Exceptions Require Royal Permission
Ultimately, the decision to enforce or override this tradition lies with the reigning monarch. Should Prince William wish to continue traveling with Prince George after his birthday, he would need explicit permission from King Charles.
Though the risk may seem small, royal officials continue to honor this tradition to safeguard the continuity of the crown.