CHICAGO (AP) – If you’re trying to make your Fourth of July last three days or more, you’re not alone.

In cars and on planes, millions of Americans are on vacation this week as the nation takes advantage of a midweek holiday.

More than 41 million Americans will travel at least 50 miles from their homes some time this week – a new record for Independence Day travel – despite heightened security because of failed car bombings in Britain.

Most travelers, 34.7 million in all, are expected to load up their cars and hit the road for extended getaways. And about 4.7 million will traipse through airports.

“We’re seeing many, many people take the week off and go for a long week (vacation),” said Beth Mosher, a spokeswoman for AAA Chicago.

Among the crowd of happy vacationers were Shannon and Darrell Harris of Hampton, Va., who traveled to Chicago on Monday with their 17-year-old son for a week of relaxation and exploration.

“We decided to come out to Chicago and see the sights,” Shannon Harris, 41, said after arriving at O’Hare International Airport. “I can’t wait.”

Elsewhere in the country, passengers who filled airports said they wouldn’t let fears of terrorist attacks ruin their long-awaited holiday.

“I must admit that I was worried, and quite frankly I still am. But I have to have faith that everything will be OK,” said Natalie Feldman, 37, who was heading from Miami to Macon, Ga., with her family. “We waited a year to plan our vacation to see family in Georgia.”

On the heels of last week’s attacks in the United Kingdom, American travelers will continue to see additional security at airports and railways.

“We clearly have ratcheted up a little bit, focusing on those places where we think there might be a heightened risk. But nobody’s really sure,” New York Mayor Michael Bloomberg said. “My advice to everybody is to enjoy the weekend.”

Amtrak officials said they were ramping up security, and the Transportation Security Administration deployed federal air marshals and security inspectors – both undercover and in uniform – to Amtrak rail stations in the Northeast.

At the nation’s airports, officials randomly searched vehicles while increasing the number of police dogs and transportation security agents.

“Our advice for all passengers – mass transit or aviation – is to remain aware of their surroundings and immediately report any suspicious activity to TSA, law enforcement or other officials,” TSA spokesman Christopher White said.

Airport officials said they expect a higher-than-usual number of travelers this week but anticipate less congestion than normal as travelers split their trips between two weekends.

By Monday evening, more than three-quarters of holiday travelers already had departed for their destinations, according to AAA data.

“I know it’s not patriotic, but we both needed a break away,” said Miami resident Rhonda Gonzalez, who was traveling with her daughter to the Bahamas on Monday.

While the Wednesday holiday was a treat to many, it was also a headache for some.

New Yorkers Alison Threadgill and Kia Wilson found themselves having to cut short their weeklong Chicago vacation to return to their jobs Friday.

“It actually ended up being inconvenient,” Threadgill said.

Still, the midweek holiday appeared to be a bonus for procrastinators because the spread-out celebration means hotel rooms still can be found at many resorts.

In Wisconsin Dells, Wis., community leaders say they still have space available but expected the lure of nearly two dozen water parks to woo thousands of vacationers.

“It’s pretty much anyone’s guess as to which weekend will be bigger,” said Romy Snyder, executive director of the Wisconsin Dells Visitor & Convention Bureau. “We have two really strong weekends.”