Check out this cool new commercial from "The Mill":

They used nCloth for some of the pillows and the airplane nets.

Basically for a pillow you want pretty non-stretchy cloth with volume conservation, but with fairly high damping(or a little deform resistance). Also air can leak out of the pillow(depending on the design), but it takes a second or two, so you could perhaps lower the air tightness a little.

There is an aspect to a pillow that is a bit like a plastic deformation where it bends it pops back, but not quite to the original shape. One might try simulating this by using the restitution angle and tension attributes.