Siblings Steven Johnson and Sandy Robbins excitedly ticked off an impressive list of tourist hot spots they planned to visit this weekend on a trip to the nation's capital.

Arlington National Cemetery, the Smithsonian, the National Cathedral and the National Archives were all listed on their rather packed itinerary.

"The last I heard, it was 85 degrees there," said Johnson of Minneapolis while waiting Thursday for a flight at the Minneapolis-St. Paul International Airport.

Spurred by a strong economy, some 43 million Americans are expected to take to the roads, rails and skies Memorial Day weekend — the unofficial kickoff of the summer vacation season — according to AAA, the national travel association.

Closer to home, 36% of 222 lodging businesses recently surveyed in Minnesota said they expect summer occupancies to increase, and 43% predict a boost in seasonal revenue, according to Explore Minnesota, the state's tourism office.

That optimism comes after a long winter and late start to spring — a dreary combination that caused nearly a third of the hotels, motels, resorts, bed-and-breakfasts, campgrounds and vacation home rentals surveyed to report a decline in spring occupancy and revenue.

"Travelers are excited to get out and discover new and unique experiences across the state this season," said John Edman, director and CEO of Explore Minnesota, in a statement.

Most people will drive to their vacation destinations this summer — AAA predicts about 37.6 million people will hit the road this weekend alone.

One possible deterrent: Gas prices have increased by more than 30 cents a gallon in the past two months, with a national average approaching $3 a gallon, according to AAA.

"This spring has pinched pocketbooks at a dizzying rate," Patrick DeHaan, a petroleum analyst at Boston-based GasBuddy, said.

But gas prices across the Midwest have generally trailed the national average. The average price of a gallon of gas in Minnesota as of Thursday was $2.72, according to GasBuddy. Prices in Minneapolis skewed as low as $2.61 a gallon.

Mo Eigen and Marisole Herling of Minneapolis are combining air travel and a road trip for their first summer foray this year. They're flying to Atlanta, then driving to Pensacola, Fla.

"It's almost 90 degrees there," Eigen said. "We're heading to the beach."

If spring break was any indication, the summer travel season at MSP should be busy, said John Welbes, a spokesman for the Metropolitan Airports Commission.

"Spring break was strong, so we'd expect summer to remain strong," Welbes said.

Year-over-year passenger traffic at MSP was up by 3.7% in March, a popular month for spring break travelers. On average, some 250,000 people are screened by security every week at MSP.

Nationwide, the Transportation Security Administration (TSA) says this season could be its busiest ever — 263 million passengers and crew are projected to clear security checkpoints between the Memorial Day and Labor Day weekends. That's about a 4% increase over last year.

Lorie Dankers, TSA spokeswoman, said MSP is "in good shape" in terms of security staffing, noting overtime will be used to extend shifts of current officers. Last week, about 200 people showed up to a TSA recruiting and hiring event. "We were encouraged by the turnout," Dankers said.

The busiest days at MSP for security screening will be summer Thursdays and Fridays, and Sundays and Mondays between 5 a.m. to 10 a.m. and 3 to 6 p.m.

Some travelers will be drawn to new offerings at the airport. Delta Air Lines will begin nonstop service from MSP to Mexico City in June, and Aer Lingus will offer direct flights to Dublin starting in July.

The AAA survey found historic European cities, such as London, Rome, Dublin and Paris, and attractions in Orlando, such as Universal Orlando Resort and Walt Disney World, are top spots for travelers. Alaskan cruises are popular, too, with Vancouver, Seattle and Anchorage topping AAA's list of embarkation ports. Steamy warm-weather destinations, including Hawaii and the Caribbean, also rank highly.

Airlines for America, a Washington, D.C.-based airline industry group, said the average inflation-adjusted domestic fare is $350. That ticket price is down nearly 16% from 2014 and is the lowest average inflation-adjusted fare since 1995, when the Bureau of Transportation Statistics began gathering ticket data.

When asked if he planned further travel this summer after his Washington, D.C., trip, Johnson said, "I may go to [Lake] Mille Lacs."