Jul 31, 2008, 11:00 GMT
Kate Middleton refused to upgrade to first class during a recent flight.
The girlfriend of Britain's Prince William - who was on her way to meet the prince in Barbados - amazed airline staff this week when she turned down their offer of a better seat.
The 26-year-old also insisted cabin crew treated her like any other passenger, saying: "Please call me Kate."
A source told Britain's The Sun newspaper: "She may be dating the future king but she's so down to earth. It's the first time we have had a passenger turn down the chance of an upgrade."
The first class ticket for the flight was worth £7,000.
Kate was making the 6,000 mile journey to the Caribbean to see the prince as he steps off the HMS Iron Duke, where he has been serving a five-week secondment.
The couple are rumoured to be spending next week on holiday in Mustique.
A source said: "Kate has really missed William. She is looking forward to spending some quiet time alone together."
William - who is known as Sub lieutenant Wales on board the British Royal Navy vessel - has been busy patrolling Caribbean waters for drug smugglers, and has so far been involved in two drug bust operations.
The source added: "As soon as the prince steps off the ship, he'll be determined to change gear and take some time out to be with Kate.
"They both agreed it was a perfect plan to enjoy two weeks together."
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