The first Boeing 747-8 Intercontinental touches down at Boeing Field in Seattle on Sunday. The plane completed its maiden flight about four-and-a-half hours after taking off from Paine Field in Everett, Wash.

SEATTLE--With the beautiful snow-covered mountains of Washington state behind it, Boeing's 747-8 Intercontinental made its first-ever landing today, four-and-a-half hours after taking off on its maiden flight.

The flight went about as well as could be expected, 747 chief pilot Mark Feuerstein said in a brief press conference at Boeing Field here, minutes after the plane touched down at 2:25 p.m. PT.

The plane, with its unique red, orange, and white livery, took off at 9:58 a.m. PT from Paine Field in Everett, Wash., and headed immediately toward the Olympic Peninsula, Feuerstein told the crowd gathered for the landing celebration, and then ultimately out to the tip of Washington state.

Along the way, he and co-pilot Paul Stemer took the plane, which is Boeing's longest, fastest, and in theory, most fuel- and cost-efficient ever, up to 20,000 feet and to 250 knots. They also flew it as slow as 105 knots during some of the approaches to stall tests. During the flight, they worked on a series of tests, including simple approaches to stalls, a couple of directional stability tests, and some functional checks of the airplane's systems. And, Feuerstein reported, everything went well, and the plane is "actually ready to go fly right now."

Although Boeing made the first flight of the 747-8 freighter on February 8, 2010, it waited until today to put the passenger version of the plane in the air. But Feuerstein said that, from the pilot's perspective, the wait was worth it. During the interim, Boeing implemented many changes and upgrades to the five 747-8 freighters in its test fleet. But while each of those planes has had a slightly different set of updates, the Intercontinental has benefited from all the various changes made as part of the freighter program. "The changes we've made on the freighter have been rolled into this airplane," Feuerstein said of the Intercontinental. "All those changes have been rolled into one airplane."

One test that he and Stemer put the Intercontinental through today was what he called a "steady heading side slip," which involves putting "the rudder all the way to the floor, and keeping the airplane tracking in the same direction by rolling the airplane," Feuerstein said. Essentially, that means they were flying the plane "sideways, but in a straight line." The idea is that seeing how it performs in such a test "tells us a lot about how it behaves...fortunately, it didn't surprise us at all."

Now that the first flight of the Intercontinental has been completed, Boeing plans on conducting about 600 hours of flight testing throughout the summer and fall, said Elizabeth Lund, the vice president and general manager of the 747 program. Then, sometime in the fourth quarter, she added, Boeing hopes to make its first customer delivery of the plane.