Earlier this year, the Travel Technology Association (Travel Tech) raised concerns about its members losing access to airline travel data, making it harder for consumers to suss out deals on plane tickets.

Now a leading senator has taken an interest in the issue. Sen. Charles Schumer (D-NY), who is expected to replace retiring Sen. Harry Reid (D-NV) as minority leader, is urging the Justice Department to investigate airlines’ practice of withholding price and flight information from price-comparison sites like Expedia, CheapoAir, Hipmunk, and Priceline.

“Some consumers may have already noticed this and others may not have—either way, this issue cannot be one that flies under the radar,” Schumer said during a Sunday press conference covered by the New York Daily News.

Schumer specifically mentioned Southwest and Lufthansa, which don’t make their fare information available to travel sites. In recent months, Delta Air Lines has also limited access to its data.

Schumer’s call comes as the Justice Department has begun an investigation to determine whether the country’s major airlines have colluded to keep ticket prices high, a probe that could shake up an industry that’s seen much consolidation in recent years. Travel Tech has already pushed for the agency to add to its investigation the issue of airlines withholding fare and schedule data from price-comparison sites.

“There is no doubt that eliminating an open, transparent market will harm consumers, because it already has,” the association said in a recent news release. “As the [Justice Department, Transportation Department], and Congress look more closely at the state of the airline industry, these and other issues should be considered.”

Airlines for America, a trade association representing the major U.S. airlines, defended the industry’s practices, saying that its members should be allowed to decide how their tickets are sold.

“Airlines, like any other company that sells consumer goods, should be able to sell their products where they believe they are best suited for their customers,” spokeswoman Jean Medina told The New York Post. “Eliminating a third-party channel isn’t going to change the wide-aperture nature of airline distribution.”

(Spencer Platt/Getty Images)