At Shenington Gliding Club we fly disabled passengers quite frequently; if the lower limbs are liable to come loose - flop around, it is a good idea to strap them down carefully.
But we also have facilities - two gliders specially adapted to enable paraplegics to learn to fly and to fly solo....and the clubhouse is also fully accessible.
Occasionally one has to call on some sturdy chaps to help with boarding and dis-embarking. But most solo paraplegics manage incredibly well, having worked out ways of gaining access. Don't have to worry about leaping out and running away from a crashed glider, it isn't likely to burst into flames...