The U.S. Travel Association typically touts America’s mountains, lakes and rivers, but today it’s talking about a cliff.

That cliff, of course, is the so-called “fiscal cliff,” the automatic spending cuts and tax hikes that will go into effect if Congress can't agree on a budget by year's end, and the leading organization representing all components of the travel industry is very concerned about what might happen if the nation goes over it.

On Tuesday, U.S. Travel CEO Roger Dow strongly urged President Barack Obama and Congressional leaders to agree on a balanced approach to solving the country's budget and deficit woes to avert the fiscal cliff.

“The U.S. travel industry is a national economic driver, supporting 14.4 million American jobs and generating $1.9 trillion in economic output,” he said. “In November, the travel industry enjoyed its twelfth consecutive month of employment growth. However, the looming combination of indiscriminate spending cuts and higher taxes for middle-class Americans will have a profound impact on travel spending, and the economy broadly, should Washington fail to act.”

Potentially significant tax increases and uncertainty over the economic impact of the fiscal cliff means many people could delay their decisions about travel, the association warned. If unresolved, millions of Americans could be left without the means to take a vacation, while businesses could cut back their travel spending substantially.

“Less travel will affect communities from coast-to-coast with small businesses paying the highest price,” Dow cautioned, adding that reduced travel might force employers to make tough decisions in a labor-intensive industry suffering from fewer customers.

On a more basic level, it could erode the nation’s travel infrastructure, making journeys into, out of, and around the U.S. by sea, land and sky even slower than they already are.

Budget cuts to U.S. Customs and Border Protection, the Transportation Security Administration, the Federal Aviation Administration and the Federal Highway Administration would likely, the association believes, create a situation where there are fewer security officers to process travelers through busy airports, ongoing flight delays and fewer updates and repairs to the nation’s highway system.

Dow said the problems would not only affect Americans but international visitors, who spent $153 billion during visits to the U.S. in 2011. He believes there is a need to remove uncertainty from the markets, reduce the nation’s budget deficit with significant long-term approaches to entitlement spending and reform the tax code to encourage American competitiveness.

In a separate call to action, the National Parks Conservation Association, or NPCA, said if Congress and the president can’t reach a budget deal, funding for America’s national parks will be slashed drastically.

The NPCA, which advocates on behalf of America’s 398 national park units, said, “National parks protect our natural and cultural heritage and provide affordable vacation destinations for American families, but the Park Service budget has already been cut by 6 percent over the last two years.”

The NPCA’s vision for the parks if Congress fails to find a solution by January is a bleak one: Closed campgrounds, vacant visitor centers and history unpreserved. The Park Service’s budget would be cut by more than $200 million, which could mean some level of closure at virtually every national park in the system, as well as reductions in park hours and the loss of a job for as many as 9,000 rangers.