Delta Air Lines and United Airlines have been sued by passengers who claim they were charged extra for a window seat but found themselves sitting next to a blank wall.
The lawsuits, filed separately against the US carriers, seek millions of dollars in damages for more than a million customers of each airline.
They said the companies do not flag that the seats are windowless during the booking process, even when charging a premium for them.
United declined to comment as it is an ongoing legal matter. The BBC has contacted Delta for comment.
The lawsuits, which are similarly worded, seek refunds of extra fees for passengers who said they had paid for window seats but got windowless ones instead.
