On a stormy day that prevented President Bush from visiting the Great Smoky Mountains National Park (search), he said "it would sure be helpful" if Congress would pass an air pollution proposal he calls "clear skies legislation."

A bad weather system moving through the Southeast forced the president to cancel his Earth Day (search) trip to the popular but polluted park, and he made his comments during a quick stop at a Tennessee airport.

The legislation is Bush's top environmental priority, and would give power plants, factories and refineries more time to reduce their air pollution.

Last month, a Senate committee rejected the bill. Opponents want a plan that also puts limits on carbon dioxide, the "greenhouse" gas scientists blame for global warming, which Bush opposes regulating.

Bush's proposal would reduce nitrogen oxides, sulfur dioxide and mercury in the air by letting smokestack industries (search) trade pollution rights among themselves, within overall caps set by the government. The plan sets a 2018 deadline for reducing the three pollutants by 70 percent.

The president pointed to moves his administration has made by executive order to deal with air pollution.

But, he added, "it would sure be helpful if Congress passed the clear skies legislation as well."

The threat of hail and thunder storms prevented the president from a planned stop to help with some quick restoration on a trail in the Smokies' picturesque Cades Cove area and delivering remarks in the park.

Instead, he talked at the airport outside Knoxville, then climbed back on his plane and departed for Texas. Bush was spending the weekend at his ranch there ahead of meetings Monday with Crown Prince Abdullah of Saudi Arabia.

Often at odds with environmentalists, Bush celebrated their holiday by claiming a solid environmental record by his administration.

"We didn't create the earth but we have an obligation to protect it," he said from an airport hangar, with a steady electrical hum and a view of the airfield providing quite a different backdrop than the White House planned. "We are meeting that obligation."

But environmentalists say Bush is not being a responsible steward, by pushing for more timber, oil and gas from public lands and relying on the market rather than regulation to curb pollution.

Bush's "healthy forests" law lets companies log large, commercially valuable trees in national forests in exchange for clearing smaller, more fire-prone trees and brush. His "clear skies" proposal would give power plants, factories and refineries more time to reduce air pollution. Environmentalists call those labels deliberate misnomers.

Bush would have been the first sitting president to visit the park since Franklin Roosevelt dedicated it in 1940, White House press secretary Scott McClellan said. The Smoky Mountains park, which straddles the border between Tennessee and North Carolina, gets more than 9 million visitors a year — the most of any national park.

It is also the most polluted national park.

The Smokies' pollution problem is due mainly to industrial soot and smog that collects in the mountains, creating vista-reducing haze, stunting plants with acid rain and threatening the health of asthmatic visitors with ozone.

Also while at the airport, he met with the families of two U.S. soldiers killed overseas.