What Prince William was never allowed to do
Air travel helps keep businesses running and families connected, but one downside is that planes do crash, even rarely. And, because the British Royal Family has experienced several tragic incidents related to air travel throughout its history, the Queen dislikes members of the Royal Order of Succession, which includes Prince William and his father, heir apparent, Prince Charles, traveling in the same plane (via BBC). For example, the Queen’s late husband, Prince Philip, lost his sister, Princess Cecilia of Greece and Denmark, as well as her children, her unborn child and several others on a small plane that s ‘crashed in Belgium in 1937 (via Little Things). Another tragic plane crash claimed the life of Prince George, Duke of Kent, in 1942 (according to the Royal Collection Trust). Then, in 1972, another cousin of the Queen, Prince William of Gloucester, died in a plane crash at the age of 30, according to the New York Times.
The Royal Family continue to travel by plane, but think of the last time there was news of William traveling with Charles. It could be traced back to 1983, when William was a baby (per Town & Country). While clearance has been granted to William and his children, who are currently number three, four and five in the Royal Order of Succession, it is possible that the Queen is growing weary of worry (via The Sun).