The American Automobile Association's annual Labor Day survey, conducted by the Travel Industry Association, found that 28.9 million people will travel by car over the long weekend, down from 29 million last year.
However, the overall number of people planning to travel more than 50 miles over Labor Day is expected to rise slightly to 34.6 million, AAA said. The number of people planning to fly this weekend increased to 4.1 million from 4 million one year ago, despite record flight congestion and delays.
Separately, the Air Transport Association of America said it expects 15.7 million passengers to fly globally on U.S. airlines from Aug. 29 to Sept. 5, a 2.6 percent increase over the same period last year.
There were no airline weather delays anywhere on the Eastern Seaboard Friday morning, reports CBS News transportation correspondent Nancy Cordes. But this summer's air travel woes haven't all been the fault of the weather.
"The problem is that the airlines are kind of a victim of their own success," Cordes said on CBS News' The Early Show. "They've got more people flying. There are more planes in the air. When there is bad weather, the system is wound so tightly that one problem at one airport can cascade throughout the entire system and then suddenly you're seeing those three-, four-, five-hour delays."
Federal relief is needed, says the industry.
"While we cannot get in the way of Mother Nature, passengers can demand that Congress fairly fund the sorely needed modernization of our nation's airspace, which can help to mitigate future delays," ATA president James C. May said in a press release.
"You really are going to enjoy the new system when it comes into effect around 2015 or 2020. That's how long it will take to retrofit every air traffic control system and every airplane with GPS instead of radar," reports Cordes. "It's not going to get rid of delays or cancellations and it will be expensive - anywhere between $15 and $20 billion."
Travelocity reported that, while airfares to international destinations continue to climb, domestic fares were down about 1.2 percent for this weekend, and 3 percent for the fall. "It's a good time to seek out vacations stateside," the travel Web site said in a press release.
Officials at Hartsfield-Jackson Atlanta International Airport were preparing for more than 1.3 million passengers to pass through the airport this weekend - a 6 percent increase over the same time last year.
Gas prices have fallen this summer to a national average of $2.75 a gallon, according to AAA and the Oil Price Information Service. That's down from $2.85 a gallon one year ago, but still high by historical standards.
"This year families appear to be concerned about the travel costs associated with an end of summer vacation, which may mean Americans aren't canceling previously planned trips but are not planning to travel more than they did last year," said Robert Darbelnet, president and chief executive of AAA.
State police in several states planned to set up random sobriety checks and have extra officers on the road.
One of the more frustrating delays for air passengers is to wait in a security line while a bag is screened for a second time, but reports a new X-ray machine being tested gives the operator two angles at once.
"Something that may look questionable on one side, when you see it on the other, doesn't look so questionable," said Peter Kant, vice president of Rapiscan Systems, which has developed the machines.
The government plans to buy hundreds of them this fall, and it could mean one day, laptop computers won't have to be pulled from their cases to be screened.