Any new suggestions? For a domestic trip in US @jrsimple used FedEx Ground for the batteries, albeit the smaller bonkas for X4: Traveling on an airplane with OpenPPG - my first trip!
A car or train may be an option.
What about overseas? I’d love to bring my SP140 to Europe this summer, can I order a new battery from OpenPPG @Pdwhite to be shipped there (Poland) instead of shipping mine? I don’t see problems with hauling the motor in checked luggage. When I move back to EU for good I would use a shipping container, like for a car or my lifetime supply of Reese’s.