Aah, gotcha. I had thought that
Probably less these days
was in reference to this part at the end of the parent comment:
cars generally float around the 32 psi area
and I haven’t seen anything to contradict all the previous literature on under-inflated automobile tires being worse for fuel economy.
Yeah it’s because the theory has been that high pressure decreases tire deformation and this is more efficient. This is where the wisdom of under inflated tires become less efficient. However lower pressure (like 80-90 psi) allows bicycle tires to absorb road imperfections and vibrations which actually ends up slightly more efficient. But if you go too low efficiency will be negatively affected.
Airplane tires actually have very high pressures to prevent hydroplaning, which is more important than ride quality or fuel efficiency for them.