One of the points of contention, if I've been reading this thread correctly,
is about whether or not the earth HAS to interact directly with the air in
order to conserve momentum. My recent thought is, NO, because the downward
moving air interacts with the surrounding air to redistribute it's momentum
and to dissipate it's energy (into thermal energy). Only if we insist on
non-interacting air molecules must we insist on conserving momentum, but
certainly such is not the case and therefore there ARE intermolecular forces
at work that can change this momentum given enough collisions with the
surrounding air molecules and the result of enough of these collisions
should be a re-randomizing of the momentum to zero. Some of the motion MAY
reach the ground (the sound/pressure wave does), but it is not necessary.
Make any sense?