The King and Queen Consort were pictured in a vehicle which arrived at RAF Northolt on Tuesday morning, reportedly bound for Balmoral, the estate on which the King's Scottish home of Birkhall is located.
The royal family are not expected to carry out any official engagements for a week after Queen Elizabeth was buried in the Royal Vaults at St George’s Chapel on Monday, as they observe a period of mourning.
According to tracking website Flightradar24, an aircraft left RAF Northolt just before 11am on Tuesday and landed just over an hour later at Aberdeen Airport.
Buckingham Palace has not confirmed that the King has travelled to Scotland.
It came as Culture Secretary, Michelle Donelan, said that most British people would see the cost of the Queen's funeral as "money well spent”.
However, she told Sky News she could not put a figure on what the total might be. No 10 has said costs for the funeral and mourning period will be published “in due course".
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Paying tribute to the volunteers who helped manage and support the proceedings of recent days, including the lying-in-state, Ms Donelan described the queue for Westminster Hall as “phenomenal”.
Around 250,000 people are thought to have had the chance to file past the Queen’s coffin as she lay in state, with queues often stretching miles from the Palace of Westminster to Southwark Park.
Ms Donelan told BBC Breakfast: “There's no dress rehearsal, is there, for this kind of scenario? It has been in the plans for years, but obviously we stress-tested everything and worked with community groups."
The outpouring of love, respect and affection was a “remarkable show of unity across the country, but also a fitting tribute to the life and legacy” of the Queen, a No 10 spokesperson added.
Among the 2,000-strong congregation at the abbey for the Queen’s funeral was foreign royalty, leading figures from UK life, and world leaders including US President Joe Biden and French President Emmanuel Macron.
The Queen was finally laid to rest with her husband the Duke of Edinburgh during a private evening burial service in Windsor attended just by close family later Monday.
No date has been fixed for the coronation of King Charles, but it is expected that, in line with royal precedent and due to the large amount of planning involved, there will be at least several months between the funeral and the crowning of the new monarch.