Last summer, the Department of Justice announced that it had opened an investigation into alleged collusion between major airlines to keep ticket prices high. Now, a group of travel agents are accusing three major airlines of also conspiring to raise prices for trips with multiple stops. 

The lawsuit, filed in a U.S. District Court in San Francisco by 41 travel agents, alleges that United Airlines, American Airlines, and Delta Air Lines conspired to close a loophole that allowed travelers to save money by combining multiple one-way tickets for the same trip.

According to the complaint [PDF], by closing the loophole, the airlines could force travelers to book a single, multi-city ticket for hundreds — if not thousands — of dollars more than if they had book tickets separately.

The airlines’ new policies, which were announced this spring, prohibit so-called “commonality” of fares, which had allowed the cost of a multi-city trip to be calculated by simply combining the price of one-way fares.

“The airline defendants, aided and abetted by ATP, agreed to increase the fares for domestic multi-city flights and no longer permit non-refundable fares for each leg of such flights to be combined to arrive at the price for the multi-city itineraries,” the complaint states.

For example, a hypothetical trip on one of the airlines from Los Angeles to Houston to New Orleans would have cost $189 using the commonality rule, but now costs $363 as a result of the policy change.

“The intent, purpose and effect of the conspiracy was and is to fix, raise, maintain, and or stabilize prices for air passenger transportation services on multi-city trips within the United States,” the complaint states, claiming that the policies are a violation of Sherman Antitrust Act as well as the California Cartwright Antitrust Act.

For their part, the airlines, which deny working together on the changes, contended when the policies went into effect that many one-way fares are promotional offers, intended to serve specific routes, not meant to be combined without routes, the Los Angeles Times reports.

A spokesperson for American tells the L.A. Times that the travel agents’ accusations are baseless, and that the airline made the “unilateral change to our fare rules to ensure that new lower fares we introduced would be available to passengers flying the route for which the fares were intended.”

Likewise, a spokesperson for American tells the L.A. Times that its policy change was made to keep travelers from combining one-way flights, “resulting in prices that were different than what United intended for the connecting itinerary.”

Consumerist reached out to Delta for comment on the lawsuit. We’ll update this post when we hear back.

[via The Los Angeles Times]

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