NEW YORK (AP) — A pair of federal lawsuits filed in San Francisco and New York this week accuse Delta Air Lines and United Airlines of misleading passengers by charging premium fees for window seats next to blank walls.

A New York law firm brought the cases as proposed class actions on behalf of any passengers who say they wouldn’t have selected or paid more for their reserved places if they had known the seats did not include a window.

“We have received a flood of interest from passengers who feel they have been harmed by this practice and who wish to join the lawsuits,” the Greenbaum Olbrantz firm said in a statement. “It makes sense that people are upset. The majority of Americans fly on one of these airlines at some point and a large proportion of them want or need a window, and they pay good money for the privilege.”

Both Delta and United declined to comment, citing pending litigation.

The lawsuit against Delta Air Lines states that when New York resident Nicholas Meyer arrived at row No. 23 for a flight to California earlier this month, he discovered the seat he bought was next to a blank wall.

At no point during the seat selection process did Delta warn him that 23F was a windowless window seat, according to Meyer, one of the lead plaintiffs.

Alaska Airlines and American Airlines also sell such seats but disclose the information when customers choose their seats, the lawsuits assert.

The lawsuits allege that United and Delta long have been aware of consumer complaints posted on social media about the windowless seats yet continued charging extra for window seats without windows.

The Delta lawsuit includes screenshots of some of those complaints.

“Your seat map should not consider this premium, nor should it call it a window seat … There is actually LESS leg room and no perks,” one Delta customer said in a post on Reddit.

The proposed class actions are seeking millions of dollars in damages from each carrier.