Thomson Aero Seating in the UK proposed an angled seating arrangement for economy / coach back in the early 2000s; no airline adopted it but they went crazy for

Thomson Aero Seating in the UK proposed an angled seating arrangement for economy / coach back in the early 2000s; no airline adopted it but they went crazy for the business-class version. Jet Blue have a special variation for their narrowbody airliners. One of the problems of angled seating is that it introduces additional lateral stresses on the body which have to be demonstrated during certification.