Resource: How to Load a Wheelchair onto an Airplane
The Open Doors Organization offers free training sessions to ground crew in how to load powered mobility devices onto airplanes. They also have cards depicting loading techniques - where to lift, where not to lift, how to pack safely, how to detach pieces - that allow for non-verbal communication in noisy areas (like the tarmac).
These are re-posted with the ODO's permission.
They also have a series of mobility-device specific tags to use, rather than the standard gate-check tags, that list specific information.