"On the day they did fly, just like today, the conditions were not ideal," Bush told a crowd of about 30,000 at the Wright Brothers National Memorial.
"The Wright brothers hit some disappointments along the way. There must have been times when they had to fight their own doubts," he said. "They pressed on, believing in the great work they had begun and in their own capacity to see it though. We would not know their names today if these men had been pessimists."
If the weather improves, organizers planned to try the re-enactment Wednesday afternoon, the climax of a six-day festival.
"A little bit of rain, the plane actually flies better," Ken Hyde, who built the Wright replica, said earlier.
Engineering professor Kevin Kochersberger was to fly the meticulous reproduction of the 1903 Wright Flyer that was built by Hyde's nonprofit group, the Wright Experience of Warrenton, Virginia.
Actor and pilot John Travolta drew cheers Wednesday from the umbrella-carrying crowd. Astronaut Buzz Aldrin, the second man to walk on the moon, delivered the invocation and singer Lee Greenwood performed "The Star-Spangled Banner."
As Greenwood finished the national anthem, a bald eagle was released in the middle of the field to the cheers of the crowd.
On Dec. 17, 1903, Orville was at the controls for that first hop that lasted all of 12 seconds. He and Wilbur alternated for four flights that day; the last, by Wilbur, lasted 59 seconds and ran for 255.6 meters (852 feet).
In the century since, travel by airplane has gone from a barnstormer's novelty act to such a routine that it brings more complaints than ruminations on the extraordinary fact that it simply can be done.
Some still remember the early wonder. John Glenn first went into the air as an 8-year-old boy in the late 1920s. Strapped into the back of a two-seat plane with his father beside him, Glenn buzzed the fields and woods near his native Cambridge, Ohio.
"We sat in the back with one seat belt strapped across the both of us," he recalled this week. "Looking down, I was hooked from then on."
As a grown man in 1962, he was the first American to orbit Earth aboard a Mercury-Atlas 6 spacecraft. And in 1998 -- some 120 manned space flights later -- he made his second trip into space, a nine-day scientific mission aboard the shuttle Discovery.
Now, at 82, he still flies his personal plane, a twin-engine Beechcraft, when he travels from his home in College Park, Maryland.
"I guess I never got tired of it. Just being able to see things as they are from that altitude, for me it's just always been an enjoyable experience," Glenn said.
In a sad reminder of the technology's perils, a small plane on its way to the flight celebration crashed Wednesday after taking off from a small airport south of Raleigh. The pilot was killed and three passengers were injured. A fifth person walked away.
The plane had flown about a kilometer (three-quarters of a mile) when it banked and crashed, said Capt. James Estes of the Lee County Sheriff's Department. The cause of the crash was unknown.
Every day, commercial airlines around the world carry about 3 million people, for many of whom the most remarkable part is the in-flight movie.