Princess Charlotte is joining her big brother George for the first time at Thomas's Battersea school next week

Summer vacation is almost over for the royal family!

Kate Middleton and Prince William returned from their annual trip to Scotland with their three kids on Wednesday after spending the week with the Queen at Balmoral Castle.

The family of five took the short trip on an economy Loganair flight and were spotted arriving at Norwich Airport in Norfolk, which is near the family’s Anmer Hall home.

Princess Charlotte walked beside mom Kate, who held 1-year-old Prince Louis in her arms, while Prince George walked beside dad William. The family’s nanny, Maria Teresa Turrion Borrallo, was also on hand.

The family trip comes one week before George and Charlotte head back to school. Four-year-old Charlotte is joining her big brother for the first time at Thomas’s Battersea, a $23,000-per-year private school some three miles from the family’s Kensington Palace Home.

“She can’t wait to be with George at big school,” an insider tells PEOPLE. “She is so excited about it all.”

Prince Louis, Prince George, Catherine Duchess of Cambridge King Power Royal Charity Polo Day, Billingbear Polo Club, Wokingham, UK - 10 Jul 2019
Prince George and Princess Charlotte
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And with two year of experience there already, George is ready to show his sister the royal ropes.

“They are close in age, and they spend so much time together,” adds the insider. “Playdates [with outsiders] can be tricky, so they learn to lean on each other.

Catherine Duchess of Cambridge, Prince Louis, Prince George, Princess Charlotte
Kate Middleton, Prince Louis, Prince George and Princess Charlotte
| Credit: Tim Rooke/Shutterstock

The royal family surprised passengers on their way to Scotland last week when they were seen disembarking from an economy FlyBe plane with their children before they they got into awaiting cars to make their way to Balmoral.

”Earlier in the flight, I’d had the feeling that someone had come on the plane that I’d recognized – but I thought it was just a footballer,” a passenger told The Sun. “We landed, and people then saw two black Range Rovers on the tarmac.

Trooping The Colour
Prince Louis, Prince William, Kate Middleton, Prince George and Princess Charlotte
| Credit: Tim Rooke/Shutterstock

“Suddenly, Will, Kate, and the kids all got up, and left. They weren’t harassed by anyone at all as they got off the plane. They just seemed like a family traveling together to be honest. No one saw them get on the plane either. It was amazing how they did it — they must have slipped on quietly, after people were already seated.”

For more than 150 years, the Scottish castle has served as a private retreat for the British royals. In the highlands, the royals like to entertain friends, hold dances, picnic and go on shooting parties – all the while battling the nibbling little flies that stalk the heather-covered mountain sides.

Queen Elizabeth and Kate Middleton
| Credit: Duncan McGlynn/Getty Images

William and Kate also joined the Queen for church services during their trip. The trio were spotted smiling and waving from their car as they made their way to church on Sunday.