Everett, Washington (CNN) -- After more than two years of delays, Boeing's 787 Dreamliner made its maiden flight Tuesday in a three-hour trip that the maker described as a success.

"Today is truly a proud and historic day for the global team who has worked tirelessly to design and build the 787 Dreamliner -- the first all-new jet airplane of the 21st century," said Scott Fancher, vice president and general manager of the 787 program, in a news release. "We look forward to the upcoming flight test program and soon bringing groundbreaking levels of efficiency, technology and passenger comfort to airlines and the flying public."

More than 12,000 employees and guests watched as the plane took off at 10:27 a.m. from Paine Field in Everett, Washington. It landed more than three hours later and about 40 miles away at Seattle, Washington's Boeing Field after having flown at a speed of 207 mph at 15,000 feet -- typical for a maiden flight, the company said.

During their time aloft, the chief pilot and captain tested some of the airplane's systems and structures while flight data were transmitted electronically to engineers at Boeing Field.

"The flight marks the beginning of a flight test program that will see six airplanes flying nearly around the clock and around the globe, with the airplane's first delivery scheduled for fourth quarter 2010," Boeing's news release said.

Boeing promises passengers "a better flying experience" that includes bigger windows, more luggage space and better lighting. It promises airline operators greater efficiency by burning 20 percent less fuel than current models of comparable size and by providing as much as 45 percent more space for cargo.

So far, 55 customers have ordered 840 of the planes. The official price of one is $150 million.

"We think this is going to be a very efficient airplane," Jim Albaugh, Boeing executive vice president and CEO, told CNN. "It's going to change the way people travel."

Despite the delays, Boeing's first new commercial airliner in more than a decade will still be relevant, Albaugh said Monday.

"It's more environmentally friendly, it's more efficient, uses less fuel, it's going to cost the operator less to fly, it's going to allow the passengers to pay less and feel better when they land," he said.

Boeing's fuel claims are linked to its design. It is the first major airliner to be made mostly of composite materials and, as a result, is lighter.

Depending on the configuration, the plane can seat 200 to 300 passengers and can travel more than 2,500 nautical miles.

But production delays and technical problems have stolen some of the Dreamliner's luster.

Many of the snags in the supply line have been blamed on the army of partners Boeing brought in to help with the construction.

"They did too much outsourcing, too soon, with too little oversight," said Scott Hamilton of the aviation consulting firm Leeham Co. "The customers have been mightily [upset] over the creeping delays."

Albaugh acknowledged that, "in hindsight," the level of outsourcing may not have been the best strategy. "There a few things we might have kept inside, yes," he said.

With 10 months of flight tests ahead, the 787s won't start flying commercially until at least 2011, the company said.

"There's a lot of work to do," Albaugh said.