Business travel in the U.S. is really taking off. 

According to The Global Business Travel Association, U.S. business travelers spent an average $72.8 billion in the second quarter of this year, a 7.1 percent increase over that same period in 2013.

And a forecast from BCD Travel's consulting unit Advito sees that uptick extending into 2015 with business travel in the U.S. and Canada set to go up 3 to 4 percent next year. The forecast looks at a number of different economic trends to predict activity in airlines, hotels, and car rental companies around the world.

As the global economy continues to improve, corporate travel is expected to follow a similar trajectory.

"It ties to the overall economic activity," Advito vice president Bob Brindley said. "Companies in general are doing well from a profit perspective. They're looking for growth and expansion opportunities, and that includes travel as a component of it."

The good news is that global airfare is unlikely to go up to much. New competition in Asia, in particular, in the form of regional low-cost carriers will put pressure on airlines to bring down fares. The bad news is, consolidation and high demand in North America is setting the stage for increasing airfare, which means U.S. domestic flights will continue to get pricier. 

Hotel costs are also expected to rise about 6 to 8 percent. The report advises that companies negotiate and work down prices both for flights and hotels. At the same time, they suggest being loyal to a couple brands, since repeat clients will have more sway when trying to lower prices.

Similarly, car rental suppliers seem to be readying price increases despite years of flat pricing. Advito expects 2 to 4 percent increase in those rates.

Businesses can learn from these forecasts and plan their 2015 travel accordingly.

"Most of our clients use it to assist them in budgeting," Brindley said. "They already know from their own business perspective of what type of activity increases or decreases they'll have from a travel perspective, and they look to us for what kind of price variances are they going to have. If they do feel that prices are going to be up slightly they may approve of some volume increases, where if prices were to grow dramatically it might cause them to cut down."