The organization expects trips from the U.S. overseas will also be constrained by worries overseas, including recession in Europe and slower growth in China.
GBTA projects international outbound spending to grow 2.5 percent this year. Less than a year ago, GBTA forecast growth of more than twice that.
Hesitation among business travelers is hurting airlines, who count on the well-heeled set to hold up their bottom lines. Business travelers tend pay more because they tend buy airline tickets closer in to their departure date than vacationers. They're also, of course, more likely to sit in the front of the plane.
On Monday, United Airlines said traffic and passenger revenue fell in September. United, the world's largest airline, is operated by United Continental Holdings Inc. Passenger revenue, which measures how much money the airlines make from fares and fees, either declined or rose less than expected among major carriers last month.
Samantha Bomkamp can be reached at www.twitter.com/SamWillTravel