Narrow body and regional jets with seats that can't even extra recline can fly for just only 3 hours non-stop! Single decker wide body aircraft with seats that can't even extra recline and narrow body and regional jets with seats that can extra recline but cannot turn into a fully flat bed are designed to fly for 6 hours non-stop! 9 hour flights should be responsible by seats that can't even extra recline on a double decker aircraft, seats that can extra recline but cannot turn into a fully flat bed on a single decker wide body and seats that can even turn into a fully flat bed on a narrow body and regional jet. Double decker aircraft filled with seats that can extra recline but cannot turn into a fully flat bed and single decker wide body with seats that can even turn into a fully flat bed should be deployed on 12 hour flights and finally 15 hour flights should be equipped with seats that can even turn into a fully flat bed on an airbus a380!