I don't think its the inspections that make planes so expensive, I
think its the way they are designed. Older cars continue to run because
they are made out of heavy, solid materials. An airplane is made out of
thin sheets of aluminum that will crack at some point. Its the effort
to make planes light that makes them break more often. Stuff on planes
is safety wired because its lighter than using heavier bolts and nuts.
Cars don't break down because bolts come undone because they have
heavier hardware. Important bolts on cars are usually also pressed on
as well as cotter pinned. Pressing aluminum probably won't have the
same effect.

-Robert