President Bush, making his way back to Washington from his Texas vacation, got a personal view this morning of the extraordinary devastation wrought by Hurricane Katrina as Air Force One flew low over New Orleans and the rest of the Gulf Coast states where whole neighborhoods and communities were wiped out.

Air Force Col. Mark Tillman, the chief pilot of Air Force One, routed the Waco-to-Andrews flight along the southern edge of the United States and brought the plane so low over New Orleans that it was barely above the skyscrapers. Bush watched intently out the window during the 35-minute flyover.

His tour took him over New Orleans and then along the coast over Slidell, Waveland, Pass Christian, Gulfport, Biloxi and Pascagoula, before the plane climbed back to normal altitude and headed toward Washington.

"It's devastating," Bush said as he watched, according to Scott McClellan. "It's got to be doubly devastating on the ground."

McClellan said Bush remained quiet through most of the flyover, while pointing out various signs of destruction along with aides. "There wasn't a whole lot of conversation going on," McClellan said. "I think it's very sobering to see from the air. And I think at some points you're just kind of shaking your head in disbelief to see the destruction that has been done by the hurricane."

The plane descended from its cruising altitude of 29,000 down to 2,500 feet as it headed toward the New Orleans area about 11:30 a.m. CST, and swooped over the city. From the air, the city appeared nearly completely washed out, with whole sections submerged and virtually no cars on the roads that were still above water.

As Air Force One moved further east, miles upon miles of residential neighborhoods could be seen completely under water. Highways disappeared into the water and at least one boat could be seen motoring down what once was a major road. Heading east to the city's outskirts and beyond, at one point dipping as low at 1,700 feet, Air Force One passed over suburban and rural communities that were virtually obliterated. Acres of forests were leveled, the trees literally flattened as if stepped on. An amusement park appeared to be a model in a bathtub, the roller-coaster emerging from the water.

Further along, the other most devastated area was in the area of the Mississippi towns of Waveland and Pass Christian, where there was not much water, but many miles of wooden houses were completely smashed, left looking from the air like nothing more than piles of matchsticks as far as the eye could see.

"It's totally wiped out," Bush said at this point, according to McClellan.

For long stretches of the coast, not a single building appeared to still be standing, and those few that were appeared severely damaged. Train cars were abandoned off the tracks. Smoke billowed up from a fire. The causeway between Waveland and Pass Christian had collapsed, rendered into nothing but rubble. Bush pointed out a church still standing while all the houses around it were destroyed, McClellan said.

Before leaving Texas, Bush discussed relief for the hurricane victims with top aides, McClellan said, and he is expected to submit a supplemental appropriation request to pay for the region's recovery.

Those participating in the video conference included political adviser Karl Rove, Vice President Cheney, Michael Chertoff, secretary of Homeland Security; Mike Brown, head of the Federal Emergency Management Agency, and others.

The meeting focused first on the current life-saving operation and then on long-term plans for recovery and relocation of people displaced by the catastrophe.

McClellan said Chertoff has declared Katrina an "incident of national significance," triggering a recently developed national emergency plan for the first time and allowing the Department of Homeland Security to better coordinate agencies.

"This could well be the worst natural disaster in our nation's history," McClellan said.

The president planned to chair a meeting later today at the White House of a task force set up to coordinate the federal efforts to assist hurricane victims across more than a dozen agencies.

McClellan also told reporters that shortly before flying over the Gulf area, Bush took a phone call from King Abdullah of Saudi Arabia who expressed condolences on the loss of life and damage from the hurricane.

"The king offered Saudi Arabia's support," McClellan said. He said the two did not discuss any increase in oil production by Saudi Arabia, but noted that he had read reports suggesting the Saudis were preparing to help stabilize oil markets.