FILE - In this April 13, 2009 file photo, American Airlines Flight Attendant Renee Schexnaildre demonstrates the adjustable seats during a media preview of the newest addition to its fleet, Boeing 737-800 jets, at Dallas Fort Worth International Airport in Grapevine, Texas. American Airlines spokesman Tim Smith said recently, the seat backs on American's new planes are curved ergonomically and thinner to provide more room around the knees.