To those who happen to travel out to rural (roadless) Alaska and plan to mail stuff back, consider that the USPS regards everything leaving as "airmail" and will only send it Priority, so plan for higher shipping.
(I know it makes no sense since the mail follows exactly the same pathways, flies on the same planes, etc, but it's what I have been told in spite of what the internet rates inform us.)
...and the rural places' Pitney-Bowes postage machines are calibrated and programmed for Priority rates only.