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Some 85% of Americans are planning at least a one-week vacation this summer and more than a third (36%) expect to spend two weeks on vacation. Car trips remain the most popular mode of vacation travel, but its appeal is diminishing. In 2014, some 44% of Americans took driving vacations, compared with a projected 36% for this summer.

Americans are also saving up for these vacations, with 81% putting aside money for travel. Fully 90% of travelers have also figured out ways to keep vacation costs lower. One such method it to use the points and rewards for various loyalty programs. More than a quarter of summer travelers plan to use loyalty program points and rewards to help pay for the summer’s vacations.

Vacationers are expected to spend nearly 20% less per person this year, however. According to the American Express Co. (NYSE: AXP) Spending and Saving Tracker, which reported these data, spending per person will fall from $1,246 a year ago to $1,005 this year.

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Less than 25% of Americans expects to travel outside the United States for their summer vacations this year. In 2011 about 55% of Americans said they were planning to stay in the country for their summer vacations.

What do these data points add up to? About 13% more Americans are planning a vacation for this summer compared with last summer, but a smaller percentage are planning to take a road trip. That could limit the demand for gasoline and crude oil — and in fact we may already be seeing some of that. According to the U.S. Energy Information Administration (EIA), the retail price of regular gasoline was unchanged in the week ending June 8, and pump prices have even come down slightly since the Memorial Day weekend.

The other implication of the data is that airlines could be looking at a solid summer travel season domestically. After all, if more people are taking vacations, but fewer are driving, there is really only one other transportation option.

While 61% of Americans will do some amount of online research before making or booking travel arrangements, 38% said they feel “overwhelmed” by the amount of information available online. To underscore that point, the American Express research noted that 16% of this year’s summer travelers are getting help from travel agencies, up from 11% last year and 8% in 2011.

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