If you go with rope, don't forget some sort of equipment to anchor/pulley with. I can't comment much more on that...

Having had the "fun" of pulling a wheelchair down the aisle in a plane, yeah, it's a PITA. The chair is just small enough to squeeze between the aisle, has 2 wheels on the back. In fact, it looks a lot like the stair-chair we used in EMS, if you've ever seen those. Anyway, if you need to evac a plane, you might be better off just "standing" as best you can and swinging off the top of the chairs, if you're able to do that much (and hopefully not sitting in the back row). Or, at 125#, maybe just catch a piggy-back off the biggest guy (...uh...or girl...) you can find.

Something else caught my eye. You mention you have brittle bones... maybe some XS Tylenol, or Vicodin, and a few splints, in case you do manage to break something? I can't imagine how difficult that would be to get to and then apply, but just a thought.

Welcome!