(Updates throughout)
By Michael Conlon
CHICAGO, Nov 27 (Reuters) - Amid tight airport security but generally favorable weather, millions of Americans took to the roads and the air on Wednesday to join family and friends for the Thanksgiving holiday, the busiest four-day travel period of the year.
Initial reports indicated smooth going for most, the notable exception being New England where a storm dumped up to 10 inches (25 cm) of snow inland and slowed traffic in Massachusetts.
Post-9/11 security measures meant lines as usual at airports. Miami's International airport initially saw 80 minutes wait time at one concourse but the crush later eased, according to Travelocity, the online booking site which deployed monitors to report conditions at 25 major airports.
At midday the longest lines were at Denver where 70-minute waits were the rule in the main terminal, and at Los Angeles International's Terminal Three, where the wait time stretched to an hour for security and baggage check-in combined, according to Travelocity.
By comparison Baltimore Washington International Airport was seeing no lines at all in three of its four terminals.
At Dallas/Fort Worth International Airport "the lines are short and brisk," said spokesman Ken Capps. He said the average wait time to pass through security checkpoints was six minutes, well below the airport's goal of 10 minutes.
BANDS ENTERTAIN TRAVELERS
The airport hired about 100 "holiday helpers" to hand out coloring books and crayons to children and giving soft drinks, popcorn and cotton candy to families.
Bands played in busy terminals at Chicago's O'Hare International and a touring group of New York's famous Rockettes handed out candy canes. O'Hare, the country's busiest airport in terms of air traffic, reported few problems after a windy morning which initially caused runway reconfigurations and some delays.
Passenger lines at Boston's Logan International Airport were lighter than normal as many travelers, fearing complications from the weather, arrived early. Some even changed their travel plans and left on Tuesday night.
Massachusetts State Police reported minor fender-benders on state highways and said some motorists had driven off roads because of the snow, which averaged between three and six inches (eight and 15 cm) across much of the state.
An early morning rush at Washington's Reagan National Airport flooded the main parking lot and travelers were clustered by the dozens at security gates.
Crowds eased slightly by midday, with many people milling casually around the concourse, drinking coffee and speaking on cellular phones.
Richard Orapollo arrived two-and-a-half hours early for his short-haul flight to Syracuse, New York.
"I heard it was going to be really busy, with people lined up all over the place. That was my expectation," he said. "When I arrived it was fine. I guess I'm too early."
In general flight delays were scattered and minor, according to the Federal Aviation Administration.
SOME WINTER WOES
Aircraft de-icing from Cleveland, east through New York state and into New England caused minor problems on the ground. Boston's Logan also reported some delays because of de-icing.
Even though more people were expected to be flying than a year ago, airlines did not add a significant number of flights because they have already cut schedules to save money during the industry's worst downturn.
Dan Stessel, an Amtrak spokesman, said service on the rail line's flagship Northeast Corridor between Washington and Boston was running smoothly despite the New England snow.
Amtrak added 58 trains to its Northeast schedule between Tuesday and next Monday and added more cars on some trains. In all it said it expected 310,000 riders in the corridor during the holiday period, about 30 percent higher than normal.
The American Automobile Association had estimated that 35.9 million Americans would travel at least 50 miles (80 km) over the four-day period, a 1.7 percent increase over a year ago. But even with the rise the shadow of terrorism was still evident -- this year's figures were nearly a million below pre-9/11 levels.
Most of the travelers -- 30.8 million -- planned to go by car. But the AAA said 6 percent more people were flying this year than last.
A 6 percent increase in air travel was also predicted by Maritz Hospital Research Group, based on a poll of more than 1,000 adults; but it disagreed with the AAA, saying its survey found that only 28 percent of Americans said they would travel this holiday, down from 33 percent a year ago.
Sunday -- when travelers who left on various days the week before all try to return home at once -- is traditionally the single busiest U.S. travel day of the year.