Delta Air Lines and United Airlines were hit with separate proposed class-action lawsuits on 19 August in federal courts in Brooklyn and San Francisco, accusing the carriers of charging premium fees for “window” seats that in fact sit beside a blank wall. The complaints say the practice affected more than one million passengers at each airline. Plaintiffs Nicholas Meyer, Marc Brenman and Aviva Copaken allege they paid as much as $100 per flight for the seats, which lack windows on some Boeing 737, Boeing 757 and Airbus A321 jets because of air-conditioning ducts and other equipment. Rival carriers such as Alaska Airlines and American Airlines flag the windowless positions during booking, while Delta and United do not, according to the filings. The suits, brought by Greenbaum Olbrantz LLP, seek unspecified damages running into the millions and an injunction barring the airlines from marketing the seats as window locations. Delta, based in Atlanta, and Chicago-based United declined to comment, citing ongoing litigation. Seat-selection surcharges form part of the ancillary revenue stream that helps U.S. airlines keep base fares lower.