WHAT IT MEANS: Most U.S.-based airlines now have a policy in place regarding large-size passengers, and you can normally find it on an airline's website under "travel information" or "special assistance." Your best bet to ensure you don't find yourself in a situation similar to Smith's is to be aware of the methods most airlines use to determine who can use a single seat:
• You must be able to attach the seat belt, though you can can use one seat belt extension if necessary (airlines normally have these on the plane)
• You must be able to sit with armrest(s) down for the entire flight if necessary
• You must not significantly encroach on adjacent seat space
Passengers who can't comply with any of these three criteria are required to buy a second seat, unless there are two open seats adjacent to each other on the plane.
If you or someone you'll be traveling with is plus-size, here are the numbers to keep in mind:
• The average armrest-to-armrest seat width in Economy class is 17 inches. In the new Boeing 777s it is 18 inches. Seats are wider in Business and First Class.
• The standard seat belt length is 47 inches. Extensions are 25 inches, for a total available seat belt length of 72 inches.
While there's no way to appeal the decision should the airline declare that you need a second seat, you can complain afterward if you feel you've been treated unfairly. Contact the airline's customer service department; you can also complain to the aviation consumer protection division and enforcement office of the U.S. Department of Transportation through the agency's website, airconsumer.dot.gov, or at 202-366-2220.