[UPDATE, Nov. 24: Forecast data from American Express Global Business Travel is included.] [UPDATE, Oct. 1: Information from NYU’s outlook on expected hotel rate increases is included.] For 2016, corporate travel buyers should expect hotel rate growth in the low- to mid-single-digit percentages while airfares on average show little change. Those are the bottom-line conclusions forecast by BCD Travel’s Advito and, separately, Carlson…