AMSTERDAM: The Dutch teenager who became the world's youngest space traveller this week surprised billionaire Jeff Bezos on the flight by telling him he'd never ordered anything on Amazon.com.

Oliver Daemen, an 18-year-old physics student, accompanied Bezos, his brother Mark Bezos and 82-year-old female aviator Wally Funk - the oldest person to go to space - on a 10-minute trip beyond Earth's atmosphere.

Bezos funded exploration company Blue Origin by selling billions of dollars' worth of stock in his online delivery business Amazon.

"I told Jeff, like, I've actually never bought something from Amazon," Daemen told Reuters in an interview on Friday at Amsterdam's Schiphol Airport. "And he was like, 'oh, wow, it's a long time ago I heard someone say that'."

Daemen, who was picked after another candidate bidding $28 million for the ride cancelled at the last minute, found out he would be joining the flight while on a family holiday in Italy.

"They called and said: Are you still interested?' and we were like 'Yes! Yes! Yes!'"

Daemen had dreamt of space travel since he was a kid, followed every development by space exploration companies like Blue Origin and got his pilot's licence at a young age.

"We didn't pay even close to $28 million, but they chose me because I was the youngest and I was also a pilot and I also knew quite a lot about it already."

PING-PONG IN SPACE

Reality still hasn't sunk in three days after the journey.

"I don't think I realised it until I was in the rocket: 'wow, it's really happening'," he said. "It was my ultimate, ultimate goal ... but I never thought it was going to be this soon."

The crew received two days of safety training, but nothing very hard, said Daemen, who can be seen in a video of the trip tossing ping-pong balls in weightlessness with Jeff Bezos.

"That was super cool. It's so weird to be weightless. It was easier than I had expected. It was kind of like being in water."

Daemen, who is set to start at Utrecht University in September, said he was not sure what he wanted to do later in life, but would seriously consider a career in space travel.

Asked what it was like travelling in a rocket ship with a billionaire, he answered with a wide smile: "They were super fun and all down to earth, as funny as that may sound."