Are there any regulations on how exit row seats have to be configured? In the past few months I have seen just about everything flying DL, US, AA, WN, CO, and NW and I know there are probably more out there. Things I notice that are different: tray tables, window shades, forward seats recline, window seat arm rest, and smaller seat cushions on window seats. Are there rows not to code or is it just up to the interior designer as to what they feel is safer?