Require airlines to reverse a proportion that can only be sold closer to the flight time (unless to a disabled person) or once the upper section is full. It see

Require airlines to reverse a proportion that can only be sold closer to the flight time (unless to a disabled person) or once the upper section is full. It seems like a solvable problem. As you note, the problem already exists - I don't see this making it much _worse_. I regularly face a similar problem on trains (I _need_ a seat due to limited mobility, and seats are a scarce resource). The train companies cope - I don't see why airlines companies can't, or couldn't be made to.