Frequent air travelers are used to dealing with headaches, from delays to crowded airports to feeling like sardines squeezed onto planes. That squeeze continues to tighten: A recent Wall Street Journal investigation proved that airplane bathrooms are getting even smaller.


While airlines typically offer up lots of technical data on their new aircraft, they don’t publish data on the size of bathrooms. The Journal’s reporter actually used a tape measure to find that bathrooms on a new Southwest Airlines 737 were about 20% smaller than those on its older planes. Many full-service airlines adopted slimmer aircraft lavatories when Airbus introduced them six years ago, and plane orders for small lavatories are now increasing faster than standard ones, the Journal reported. When late adopter American Airlines introduced its first smaller aircraft bathroom last fall, pilots and flight attendants complained about it in meetings with senior executives, according to the Journal.


Of course, this trend is nothing new. To maximize their profits and margins, airlines have been getting more money out of passengers for years, either through ancillary revenue (baggage fees, flight change fees) or by maximizing the number of seats through smaller seats and narrower pitch (the distance between a row of seats). The typical aircraft has a life span of 15 to 20 years, flying three or four rotations a day, so having six more passengers buy tickets for those seats adds up to a lot of money.


Smaller bathrooms hurt corporate passengers the most. They travel a lot, and look for comfort. The Journal article notes that bathrooms in first class are larger than those in coach, but airlines don’t really advertise it. That’s for good reason: By advertising that their first-class bathroom is bigger, they’d also be saying that their bathroom in coach is small. It’s something that everyone who flies first- or business-class knows anyway.


On the other end of the spectrum are ultra-low-cost carriers like Spirit Airlines, whose business model is to get passengers who are willing to pay very low fares from point A to point B, and not minding much if passengers are disgruntled. Southwest tries to have it both ways, balancing the need to maximize profits while avoiding the perception that it’s “nickel and diming” consumers through its “transfarency” campaigns that advertise that the airline doesn’t charge baggage fees. But quietly, Southwest, too, is installing smaller bathrooms and adding more seats. Still others, like United and American, nickel and dime passengers who buy basic fares with flight change and baggage fees, while offering other types of fares for corporate travelers. You can’t do that for a bathroom, though.


The market will decide how far this trend goes. Carriers with primarily corporate customer bases may one day start giving some room back. If one airline starts flying aircrafts with larger bathrooms and advertises it, the others will follow and change, too. For ultra-low-cost carriers, though, this isn’t very likely. Other ways that the trend could end are customer complaints, potential lawsuits because passengers are injured in small bathrooms, or government regulation. The U.S. House recently passed legislation, now moving on to the Senate, that would allow the FAA to regulate minimum seat size and leg room on planes, citing cramped seating as a safety issue.


Any end to smaller bathrooms really hinges on an airlines’ customer base. If the carrier has a lot of corporate passengers, it’s possible, and if it’s an ultra-low-cost carrier, the squeeze is likely here to stay.