Corporate travel managers worry that changes to Delta Air Lines’ frequent flier program will cost their companies money, with employees booking higher-priced tickets in order to nab bigger rewards.

A survey conducted by the Business Travel Coalition found that 84 percent of travel executives are concerned about rising costs of business travel as airlines increasingly reward frequent flier points based on dollars spent, not miles flown.

Many corporations pay for company travel but let employees keep the frequent-flier miles. Most of the 66 travel executives surveyed fear the new system will create an incentive for employees to delay booking until the last minute or seek other more costly options, instead of finding the cheapest flight for their companies.

“This new loyalty program direction will result in our employees looking for loopholes to book higher fares,” one survey respondent wrote. “We will once again become the Travel Police.”

Starting next year, Delta will join Southwest Airlines and some smaller carriers in awarding frequent flier miles based more on dollars spent and less on miles flown. Some expect that system to spread to other carriers. Atlanta-based Delta is the Twin Cities dominant carrier.

The March survey, released Thursday, also found that 95 percent of travel managers worry it will be harder to control travel costs as airlines give perks based on ticket prices.

Photo Credit: A passenger talks on her phone at a Delta Airlines gate a day before the annual Thanksgiving Day holiday at the Salt Lake City international airport, in Salt Lake City, Utah. George Frey / Reuters