AUGUSTA – Thousands of people were flying out of Maine’s airports and hundreds of thousands of vehicles took to the highways Wednesday as Mainers planning holiday visits made the eve of Thanksgiving one of the busiest travel days of the year.

“It’s been a very smooth day across the board,” said Portland Transportation Director Jeff Monroe, adding that bus lines added trips and Amtrak prepared for added riders to meet the heavy holiday demand. “It’s a very busy travel day.”

It was the busiest day of all on the Maine Turnpike, which was expected to be used by 220,000 vehicles on Wednesday, said spokesman Dan Paradee.

The heaviest traffic would be in the evening as travelers bound for turkey-day visits mixed with regular workday commuters on the toll highway.

The good news, said Paradee, was that motorists were headed in both directions, not just north or south as they typically do during summer holidays. Turnpike construction was suspended for the holiday weekend in hopes of avoiding tie-ups, he said.

At Portland International Jetport, where long lines were already forming before dawn and numbers remained “steady and strong” through the day, travelers showed they have grown accustomed to heightened security by showing up for flights early, said Monroe.

“People have heeded the advice of giving themselves extra travel time,” said Monroe, adding that 2,500 to 3,000 people were expected to fly out of the jetport on Wednesday.

Officials at both the Portland and Bangor airports expected traffic to be at least as heavy on Sunday, the day nearly all travelers return home.

Bangor International Airport Assistant Director Tony Caruso advised passengers to give themselves a two-hour cushion before their flights. And for those carrying presents: Leave them unwrapped so security officers can see them, Caruso suggested.

Weather conditions didn’t appear to be much of a factor on Wednesday in Maine, but the National Weather Service in Gray predicted rain over most of the state during the daytime on Thanksgiving, with thunderstorms possible in some parts of southern Maine.

Maine’s weather situation was much better than that of other parts of the country. Heavy snow in the nation’s midsection and thunderstorms in the South snarled traffic and contributed to long lines and big crowds at some airports.

Maine State Police planned to put extra patrols on the state’s highways throughout the holiday weekend. Col. Craig Poplin, head of the state police, urged drivers to be well-rested, to plan ahead and to avoid drinking and driving.

Maine seemed to be skirting snow as the holiday period began, with grass still green even in the far-northern town of Madawaska, town clerk Manon Bilodeau said.

“It’s definitely not going to be a white Thanksgiving,” Bilodeau said.

Gov. John Baldacci planned to spend part of his holiday serving turkey dinners to patients and staff at the Riverview Psychiatric Center in Augusta. Later, he planned to dine with his family at the Blaine House.

The kitchen staff at the Maine Correctional Center began preparing 550 pounds of turkey and nearly a half ton of stuffing, potatoes, butternut squash, and other trimmings including pumpkin pies for the 758 men and women inmates, said Superintendent Scott Burnheimer.

“They’re working like the devil today,” said Burnheimer, who also noted that Thursday’s reservation list at the South Windham compound’s visiting room was full.

Public events were planned for Thanksgiving in some of Maine’s towns and cities to usher in the Christmas season. In Caribou, a Christmas tree lighting and arrival of Santa Claus was scheduled.