One of the most disappointing seats on a Boeing 737 is central to a lawsuit filed in a federal court in San Francisco this week. A San Francisco man joined the class action suit against United Airlines Tuesday, alleging the airline charged him extra for a window seat that was actually next to a wall.

Delta Air Lines and United Airlines were sued on Tuesday by passengers who claimed they paid extra money to sit in “window” seats, only to find themselves placed in seats next to a blank wall.

However, while competitor airlines like American and Alaska Airlines flag these seat kinks during the booking process, Delta and United do not — even while charging tens or hundreds of dollars for the...