The era of phenomenal growth in the U.S. travel industry may be nearing an end.

That warning was delivered last week by Joseph G. Smith, president of the research firm of Oxtoby-Smith Inc., who said the giant industry must adjust or suffer the consequences.

"We [in the travel industry] are living . . . with a new state of affairs," Smith told the 1980 Travel Outlook Forum. "It is a state of affairs which requires better, sharper, tougher marketing. We are going to have to learn from the experiences of those industries which have not been blessed with a heavenly ordinance of growth."

Smith's assessment is based on the results of a 700-page "Travel Pulse" survey conducted by Oxtoby-Smith with Travel and Tourism Consultants Inc.

The report measures past performance and anticipates trends in almost every segment of travel from hotels to cruises. Interviews were conducted with more than 3,600 person to determine consumer sentiment and past and future behavior patterns.

The number of people who said they definitely planned to take a pleasure trip in the next year stood at 39 percent in October, down 11 percentage points from a year ago.

Only half of those surveyed said that they enjoy traveling and travel whenever possible. In 1979 and 1978 the survey showed two-thirds of consumers felt that way.

One out of every four persons said they did not travel because of the difficulties and hassles.

"What we see in the consumer is a sense of uncertainty, of caution, of anxiety, of indecisiveness that is nothing less than pervasive," Smith said.

Nevertheless, the report found that the basic psychological need to travel, to escape boredom and routine, is strong. But the need to travel, unlike other basic needs, is postponable. "I want to shake the industry up with that recognition," Smith said.

Two factors have contributed to this state of affairs, he said. One is economic, and there is not much anyone can do about that. The other is a failure on the part of the industry to understand what people want and then try to offer it to them. This stems from a belief that growth is implicit and preordained. With only a few exceptions, travel professionals rarely have taken any kind of marketing initiative.

"Travel is afflicted with a management-by-miracle syndrome," Smith said in an interview. "And the consequences can be very grave for an industry of such seminal importance."

Smith told the forum audience that travel and tourism should perhaps be marketed like shampoo or other packagable products. The divergent elements of the travel industry need to learn to "find opportunity and need and develop a product for it," Smith stated.

One pattern the travel report shows is that more people are taking shorter trips, both in terms of time and distance. Smith said that someone could take advantage of this fact and design a product to suit such a traveler.

"The big point is that the growth is gone, and it's naive to wait," Smith said. "The number of bodies traveling, the number of trip days -- it's all very flat. The things I see depressing the industry, there's no reason to expect that these forces will disappear. I don't see a return to the halcyon days."