A fierce snowstorm pummeled the Midwest on one of the busiest travel days of the year Wednesday, snarling roads and causing long delays at airports as millions of Thanksgiving travelers tried to make it home for the holiday weekend.

The National Weather Service (search) said parts of Illinois got up to 8 inches of snow, while 7 inches were reported outside Kansas City in the Midwest's first major snowfall of the season. The region was also hit by strong thunderstorms, high winds and icy conditions that made driving treacherous.

The snow caused dozens of flight cancellations and three-hour delays at Chicago's O'Hare International Airport (search), where city officials expected more than 1.4 million travelers to pass through by Sunday night.

According to a survey conducted for AAA by the Travel Industry Association of America (search), 30.6 million people, or 3 percent more than in 2003, were expected to hit the road during the holiday weekend, even with gasoline prices nearly one-third higher than a year ago. An additional 6.6 million are likely to travel by plane, train or bus.

Matt Swanson, a student at Chicago's Moody Bible Institute, said he was considering driving to Minneapolis after his flight from O'Hare was canceled.

"You can't control the weather, it happens and there's not too much you can do about it," he said.

In Michigan, a Northwest Airlines jet carrying 87 passengers and four crew slid off a snow-slickened runway while landing at Lansing's Capital City Airport. No one was injured. Bad weather forced Northwest Airlines to cancel a total of 37 flights, including 22 into or out of Detroit.

The snowfall was accompanied by high winds in spots. The National Weather Service reported gusts of 57 mph around Champaign, Ill. High winds along Interstate 74 near Greensburg, Ind., caused a semitrailer to overturn, leaving the highway strewn with debris.

In Indiana, severe thunderstorms cut across the southeastern part of the state, as heavy snow fell to the north.

"We've had quite a few crashes — slideoffs, fender-benders and people ending up in ditches, but no injuries," said Indiana State Trooper Tom Szymanski.

Elsewhere in the country, highways were bumper-to-bumper in Georgia as drivers faced thunderstorms and a threat of tornadoes, part of a system that killed at least four people elsewhere in the South.

"We're seeing some hectic and chaotic driving situations — the road rage, the rear endings, people not allowing other motorists to change lanes," said Georgia State Patrol Trooper Larry Schnall.

At the Atlanta airport, many flights were delayed and a few were diverted because of the severe weather in the region.

The weather was also disrupting travel in the Northeast. Airports in New York City, Boston and Newark, N.J., were experiencing delays up to two hours because of rain.

Adriano Maniaci's flight from Orange County, Calif., was an hour late getting into O'Hare, but he was happy to make it there safely.

"I just can't wait for tomorrow now to be with my family and eat lots of turkey," said Maniaci.

Meanwhile, drivers cruised through Pennsylvania Turnpike toll plazas for free Wednesday after toll collectors and maintenance workers went on strike hours before the holiday rush.

In Oklahoma City, hundreds of airline passengers were delayed at Will Rogers Airport after a passenger got through a security checkpoint with a box of ammunition. A concourse was evacuated and passengers on at least two flights were ordered off planes to be rescreened, airport spokeswoman Karen Carney said.