The move of some airlines to deny online travel agencies (OTAs) access to their price data to deter airfare comparison could result in ticket prices rising by more than 11 percent.

Prices could rise to $30 more on average per ticket or an increase of about $120 for a family of four making a trip, according to the report titled "Benefits of Preserving Consumers' Ability to Compare Airline Fares" released by the Travel Technology Association (TTA) recently through its website.

The lack of access to transparent, comparable airfare information would be costly to some 223 million American leisure and unmanaged business travelers, as they might pay $6.7 billion more in airfares, according to the report authored by Dr. Fiona Scott Morton, R. Craig Romaine and Spencer Graf.

Morton is a former Deputy Assistant Attorney General for Economic Analysis for the Antitrust Division at the U.S. Department of Justice and is currently a professor of economics at the Yale University School of Management. Romaine and Graf are from the consulting firm Charles River Associates.

The TTA commissioned the economic impact study to determine the price American consumers could pay because of restrictions currently being placed on airfare information transparency by some airlines.

Some OTAs accuse Delta Air Lines of blocking access to airfare and flight schedule. Delta pulled that information from TripAdvisor, Fly.com, Hipmunk, and Routehappy last year, as well as from a number of European OTAs this year, reasoning that they did not have permission to use its data.

Delta also denied airfare information to metasearch sites such as Hipmunk and Kayak, which offer fare tables based on data compiled by other price-comparison sites.

Early this year, Delta prevented OTAs from distributing information related to Delta flights to Skyscanner.

"Delta reserves the right to determine who it does business with and where and how its content is displayed," a company spokesman said in an email, according to The New York Times.

The more transparency there is in pricing, however, the easier it is for consumers to comparison shop, the TTA report said.

"Consumers should be able to comparison shop," said Philip Minardi, director of communications of TTA, according to MainStreet. "It pushes prices down. Anti-competitive actions could be devastating to travelers."