Days after Prince Harry and Meghan Markle received a lot of criticisms for using a private jet on their trips, Prince William and Kate Middleton showed up at a Scotland airport to ride a commercial airplane. The Cambridge couple were likely headed to Balmoral with their children and a full entourage, including Duchess Kate's mother.  

According to Daily Mail, Prince William and Duchess Kate flew economy with the airline FlyBe. They took the 8:45 a.m. flight from Norwich to Aberdeen and were witnessed by a slew of other passengers. It's estimated that the travel cost the Cambridges' trip was less than £400 compared to the £20,000 that Prince Harry and Duchess Meghan's flight's cost. 

One frequent flyer told the news outlet that the Cambridge family sat in front of the economy plane, and no one was aware they had royals on board. It wasn't until the passengers had to step down on the tarmac that everyone noticed Prince William, Duchess Kate, the children -- Prince George, Princess Charlotte, Prince Louis -- nanny Maria Borrallo and Carol Middleton. 

"A cynic might say the Cambridges have done it deliberately, bearing in mind all the recent stories about the two brothers and their wives not getting on," royal expert Phil Daphier told Daily Mail. "Could this be William and Kate hitting back? At the very least they would have known they would have been criticized if they had taken a private jet."

Meanwhile, sources say that Prince Harry, Duchess Meghan and their baby son Archie Harrison won't be reuniting with the Cambridges at the Queen's castle and summer hideaway in Balmoral. The Duke of Sussex has an engagement on Saturday, Aug. 24, with the Rugby Football League, per 9Honey.

As a patron of this organization, Prince Harry is expected to be at the finals on Saturday at Wembley Stadium. So, it's likely that the Sussex royals are skipping the family gathering this weekend. 

Sources told The Sun that Prince Harry and Duchess Meghan plan to go to the Queen's summer home in September. By then, Prince William and Duchess Kate would have other commitments. The Cambridge couple usually spends summers at Balmoral after the bank holiday with the Queen's other grandchildren, Peter and Zara, and it's the schedule they have been following since it's also a great time for the kids to play with their cousins.