Americans are expected to hit the roads, skies and seas in record numbers this summer -- making this the best summer travel season in years and topping levels not seen since before Sept. 11, 2001.

The Travel Industry Association of America (search) expects leisure travel to climb more than 3 percent from a year ago, while spending on those jaunts could jump more than 4 percent.

Experts attribute Americans' newly adventurous spirit to a recovering economy and a newfound feeling of comfort with air travel and safety issues.

"First and foremost, people have more confidence in the economy. Travel is strongly correlated to people's confidence and their belief in the economy. So that's certainly healthy," Michelle Peluso, CEO of Travelocity.com (search), told FOX News. "Secondly, consumers now know what it's like to live under a yellow security threat, and they're getting more confident about going out and traveling in that environment."

Travel Web site Orbitz (search) also said it expects 2004 summer travel to reach pre-Sept. 11 levels. And Cathy Keeffe, spokeswoman for TIA, said travelers are becoming more savvy about taking trips in a world where terrorism is a known threat.

"I think Americans have accepted what I term this 'new reality,'" she said. "We're going to have to live with terror alerts. We have to deal with orange alert this and that."

Ultimately, Keen said most people have made the decision to continue with their lives rather than avoid tourist destinations out of fear.

"You have a choice as an American and as a consumer and as a traveler. You can hole up on your house or be more aware and live your life the way you always did."

Travel deals and cheap tickets are also coaxing people out of their homes. According to Travelocity, the major air carriers put 35,000 markets on sale this spring, including popular spots like Las Vegas, California and Hawaii.

Indeed, the most popular destinations -- in order -- are Florida, California, Hawaii, New York and Colorado, according to the TIA. And the hot spots make perfect sense, since Americans are primarily looking for ways to enjoy the sun and sand this summer.

"The popularity of going to the beach or a lake went way up this year, to 73 percent," said Keeffe. "Last year it was just 67 percent."

Amusement parks are also cashing in this summer. Universal Studios, for instance, is experiencing double-digit increases in attendance compared to last year.

And while more Americans plan to vacation relatively close to home, Keeffe said air travel is on the rise.

"We expect to see a 5 percent increase in air travel volume. Those long haul trips are coming back into play."

All of this travel is happening despite a big jump in prices at the gas pump. A gallon of gas is going for 27 percent more than it did July 4 last year, although prices have eased since Memorial Day weekend.

"Gas prices won’t cause people to cancel trips, but they will modify them," said Keene. "Fifty-one percent said that they planned on staying closer to home."

But whether Americans go to far-flung spots or stay within their home state, the bottom line is that nothing's getting in the way of those summer vacations -- not high gas prices, not security hassles, not even terror fears.

Fox News' Dagen McDowell and Marla Lehner contributed to this report.