Space shuttle Discovery flew over captivated crowds of space enthusiasts for the last time today before being retired to a museum.

Thousands gathered to watch the retired spacecraft as it rode on the back of a 747 jumbo jet that took off from Kennedy Space Center in Florida at dawn Tuesday. The pair headed up to the Washington Monument and White House, where thousands more crowded for a glimpse the shuttle's final, mid-morning salute.

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Jason Zengerle and his five-year-old son Asa travelled 4.5 hours from North Carolina to watch the flyby at the Washington Monument. (Sylvia Thomson/CBC)

Jason Zengerle made a 4.5-hour journey from North Carolina with his five-year-old son Asa in hopes of seizing their last chance to see the shuttle in flight. They approached the mall at the monument just before 10 a.m., catching sight of the flyby from the window of their cab. They were disappointed, thinking they had missed the big salute. Then, to their delight and that of the thousands gathered with them, the shuttle flew by twice more.

"It is just beautiful," said Olivia El'Amin, who used her iPhone to shoot video of the flight. "I am overjoyed. I will share this history with my grandchildren."

El'Amin, who works for the IRS, said her supervisor gave employees special permission to leave work and watch the shuttle flight. She added that she and the rest of the crowd were out to show support for NASA.

Following the flyby, the shuttle and jet landed at Washington Dulles International Airport. Discovery was to be towed Thursday to the Smithsonian's National Air and Space Museum annex in northern Virginia.

NASA working on Orion

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The shuttle ended up making several flybys, to the delight of thousands of onlookers. (Sylvia Thomson/CBC)

Discovery was the most travelled vehicle in NASA's shuttle fleet, flying nearly 240 million kilometres over 39 orbital missions before retiring last year.

NASA's two other remaining shuttles, Endeavour and Atlantis, also ended their service last year when the U.S. space agency wound up its 30-year-old shuttle program.

Endeavour will go on display at the California Science Center in Los Angeles, while Atlantis will remain at the Kennedy Space Center.

NASA is working on a new space vehicle called Orion, but it isn't expected to be ready for its first test flight until 2014.

In the meantime, NASA astronauts will be relying on Russian Soyuz spacecraft to get to the International Space Station.

Some private U.S. companies, such as Space Exploration Technologies Corp. or SpaceX, are also hoping to transport astronauts in the future. SpaceX is scheduled to make a demonstration launch of its Falcon rocket on April 30.

With files from CBC's Sylvia Thomson and The Associated Press