A Flybe spokeswoman said: "We were delighted to welcome the Duke and Duchess of Cambridge and their family on board one of our flights again, this time when they flew from Norwich to Aberdeen on a Flybe flight operated by Eastern Airways".
Prices for that route start at £73 ($89), with a fully flexible fare costing £249 ($303).
Photos showed Prince William carrying bags across the tarmac before taking his seat on the plane for the one-hour and 15-minute flight.
Available at the bottom of the page is a video of the royal couple, the future King of England and his spouse, together with their 3 children and Kate's mother, as they're being escorted off the plane, towards their chauffeured ride.
Passengers on the flight did not realize that the royals were on board as they boarded separately.
Other celebrities chimed in to say pretty much the same as Sir Elton: members of the Royal Family couldn't board a regular plane, with regular people because of safety concerns.
He added: "William and Kate flying on a budget airline proves you can do it".
Earlier in August, Prince Harry said he plans to have to children "maximum" in order to protect the planet, during a conversation with environmental activist Jane Goodall in an edition of British Vogueguest-edited by Markle. John said he had paid for the jet for security reasons and had also paid for carbon offsetting of the flights.