My personal opinion is that DL
's configuration on the 767-400 is the best for space. Although the seat is not actually bigger, all seats have aisle access in the staggered layout and the space above the feet of the row behind is appreciated shoulder space. However most of their 767s still have the old business elite seats which are not as good. They are a bit narrow and not flat.
's new seat are very similar. CO
's seat is at an angle (seat does not face forward), so it isn't a true 2-1-2 configuration since the seat is a bit narrower since it is at an angle. The UA
seat is staggered facing forwards and backwards which shrinks the foot space when in flat mode, but that is only a concern if you are taller.
In general if you want a good seat, take a DL
764 or UA
763 as they are the only fleets that have full flat products across their entire fleets. They are all big improvements over what the older seats are like. The two airlines with lower quality seats are AA
and US. AA
's angled flat seats aren't as good for sleeping, and the PTV is not built in. US has an old outdated product on the 767s.
If you have never designed an airplane part before, let the real designers do the work!