A flurry of excitement was sparked when the royal boarded the plane, with passengers reaching for their mobile phones to snap a photograph of the Prince, whose short visit to the USA has provoked a case of royal fever.
Passenger Sam Kim posted a shot on Instagram of the Prince searching for his seat, with the caption: "Our flight was delayed and a caravan of black suburbans pulled up to the plane.
"Then the most unexpected guest stepped onto our DC shuttle flight this morning."
Another passenger snapped a photo of William about to take a seat. Alongside the picture he tweeted: "Flying with Prince William to DC !! #PrinceWilliam #DukeofCambridge #USAirways @AmericanAir @USAirways."
CNN journalist Anderson Cooper tweeted the news of the star passenger to his more than five million followers.
"Prince William just got on my DC shuttle flight", he announced on Twitter, before joking, "I'm hoping this means an on time departure".
After a smooth flight, William was given a tour of the White House by Vice-President Joseph Biden and his wife Dr Jill Biden ahead of his meeting with President Obama.
With the president himself, he found himself talking about his and Kate's fast-approaching arrival – due next year.
"Last time, I remember when George was born, I forgot to work out whether it was a boy or a girl," he said. "The excitement of the event and everything else was just chaos.
You are suddenly... well actually it's a boy. So now, it's good."
"It's going to be interesting next year. A busy year next year," he added.