According to a recent report, more Americans are planning to go on vacation this summer than in previous years, and plan to spend more money when they go. And, since Fourth of July weekend is the most popular travel weekend of the summer, now seems like a great time to figure out how this could impact your portfolio.

There are several industries that should benefit from this, but the big winners could be the companies who focus on processing payments, such as American Express (AXP -0.84%), Visa (V 0.05%), and MasterCard (MA -0.08%).

More travel and more money to spend
A clear sign that the economic recovery in the U.S. has made tremendous progress, 75% of Americans are planning a summer trip of some kind. This is up from 69% last year and vastly improved from the 59% of Americans who took a vacation in the summer of 2012.

flickr/ neilsphotography

Not only are more people planning to travel, but those travelers plan to spend more money. The average traveler says they expect to spend nearly $1,250 per person during their vacation, up 9% from just last year.

So, between the higher number of travelers and the higher spending per traveler, summer vacation spending could climb by more than 18% this year. This means billions of dollars in extra spending will be up for grabs.

Who could benefit?
There are several industries that should see a nice share of this extra spending.

The obvious beneficiary should be the travel industry, especially airlines and hotels. And don't forget companies who facilitate travel planning like Priceline.com. The percentage of Americans who say they will use online tools such as travel websites when booking their summer vacations rose from 56% to 63% this past year.

Retailers could benefit, especially clothing retailers, a group which has struggled lately. In fact, one survey listed "buying new clothes" as a top pre-travel activity. This could provide a much needed boost to companies such as American Eagle, Aeropostale, and others.

However, instead of trying to guess which industries will get a big chunk of travelers' spending cash, I'd prefer to go with a sure bet.

The big winners
The one group that is sure to be a winner here is the payment processing companies like Visa, MasterCard, and American Express.

All of these companies pocket a fee every time someone swipes their credit card, and many travelers prefer to use cards rather than carry lots of cash in unfamiliar places. Plus, the most expensive parts of vacations are things like airfare and hotels, and how often do people pay cash for those?

Think beyond summer
According to the U.S. Travel Association, the travel industry generated about $2.1 trillion over the past year between direct and indirect spending.

If this turns out to be something more than just a summer trend and means the overall travel industry is improving, this growth could mean big bucks for the payment processors.

Using the same 18% increase in total amount spent as we stated earlier, this could mean an increase of travel spending of about $380 billion per year. Even if the average payment processing fee is 2%, which is a very low estimate, this could mean an additional $7.5 billion in fee revenue for the payment processors. While this is a generous estimate, because people aren't going to charge 100% of travel expenses, there is still pretty impressive potential here.

When you consider these companies' total profits for the entire year of 2013 were $5.8 billion (Visa), $3.1 billion (MasterCard), and $5.2 billion (American Express), it's easy to see how a sharp increase in travel spending could have a big impact on the companies' bottom lines.