Duke and Duchess of Cambridge catch a ride back to London in their friend's helicopter The Duke and Duchess of Cambridge landed at Denham, Buckinghamshire A friend picked them up from North Wales and dropped them off there An aircraft carrying Prince Charles and Camilla was forced to land there last month As hitch-hiking goes, it's not normally a helicopter that stops to provide the transport. But then it's not every day that the passengers getting a lift are the Duke and Duchess of Cambridge. William, Kate and pet dog Lupo were the recipients of a free ride from a friend flying past their home in North Wales. He picked them up then, after a 200 mile flight, dropped them off at an aerodrome on the outskirts of London. Homeward bound: The Duke and Duchess of Cambridge and dog Lupo with Simon Oliphant-Hope after landing at Denham, south Buckinghamshire Coming in to land: The Duchess of Cambridge can be seen through the helicopter window (right) as it touches down in Buckinghamshire Their arrival was photographed by a surprised - and delighted - couple watching light aircraft taking off and landing at Denham in south Bucks. When the brightly coloured helicopter arrived at the small grass airfield they had no clue to the identities of the VIPs aboard and didn't initially recognise them. They said: "We had no idea it was the royal couple at the time. We had a look at the photos on our laptop a few days later and realised that it was in fact Prince William and Kate. It's amazing to think that we saw the royal couple without any crowds around them. They were like any other couple out with their dog - albeit having just been flown in by helicopter. Lupo was very well behaved. Kate let him down on to the grass and he stayed close, although you could see he was excited. Taking charge: Prince William is seen talking to the helicopter pilot while Kate (partially obscured left) is seen holding on to Lupo Denham must be getting used to Royal visitors dropping in. A week earlier the Prince of Wales and the Duchess of Cornwall had to make an emergency landing in their helicopter at the airfield. Charles and Camilla were 15 minutes into their journey to the Hay Festival in Wales from central London when a "technical problem" with the rear rotor blade forced their pilot to divert to the nearest airfield. Dressed down: Prince William was dressed slightly more casually than when he was pictured at the wedding of Thomas Van Straubenzee, 30, and Lady Melissa Percy, 26, at Alnwick Castle on Saturday The aircraft, understood to be carrying seven people, made an urgent controlled landing - later described as "hairy" - at Denham and the royal couple continued their journey by road. The orange McDonnell Douglas helicopter carrying William and Kate belongs to Shoreham-based Eastern Atlantic Helicopters, whose managing director Simon Oliphant-Hope is a friend of the couple. The four-seater is no ordinary aircraft. In 2004 Mr Oliphant Hope used it to circumnavigate the globe in a record time, flying solo around the world in just over 17 days. The "Royal" flight last month was not on the same scale, the trip taking around 90 minutes - a distinct improvement on a car journey that would take nearer five hours. Both William and Kate were casually dressed in jeans with her baby bump clear to see as they walked away from the aircraft, which bears an uncanny resemblance to Budgie, the little helicopter in Sarah Ferguson's children's book. Kate carried cocker spaniel Lupo from the helicopter but let him loose to run obediently alongside the couple as they walked across the grass airfield . The Duke drove off in a Range Rover while Kate, who is due to give birth to their first child next month, left in a separate vehicle. Mr Oliphant Hope, 49, said: 'I know the couple and occasionally, when I am routing past North Wales, I give them a lift if it is convenient to all parties. Who was behind the controls of the US-registered helicopter is unclear. Mr Oliphant, who in 2009 provided a helicopter for David Cameron to travel to a conference in Harrogate, wasn't saying. While he and Anglesey-based RAF search and rescue pilot William sat in the front with Kate, Lupo and a Royal detective in the rear, that model of helicopter can apparently be piloted from both right and left seat. A Royal source said: "The flight wasn't paid for and the helicopter wasn't chartered. There was no cost. It was a gift, a lift from a friend. VIP landing zone: Denham is no stranger to royalty landing at its airfield - a helicopter carrying Prince Charles and Camilla had to make an emergency landing there a week earlier