And, of course, there are many different degrees of blindness. Some people just have very low vision (but can actually see things); others may just see light and dark; some do not see anything at all. It seems that each one of these would be a different case. Even if there were a caretaker traveling with the person, the caretaker could be injured in an accident and the disabled person may still be on their own. Thankfully, the rate of airplane accidents is exceedingly rare these days.