This is a very controversial topic. Like all true "controversial" issues - there are many sides.
A good service provider, would do just that - provide good service based on the individual needs of the clients. It shouldn't rest on a "classification" allotted to you by the government that determines whether you get good service. And if they can provide extra service to those who need it more power to them, if they can't then it shouldn't be presumed that they are just being stubborn or obstinate or crappy service providers. Many service providers spend a lot of time and energy balancing the needs of the many against the needs of the few. The resulting formula is often the basis of their customer service approach. Most companies would go out of business if they truly had 100% happy customers all the time.
I have RLS (Restless Leg Syndrome) and I often have an attack after being immobile for a period of time - airlines are the worst. I suppose I (and others like me) could require that exercise areas be set aside on an aircraft....
Would the other passengers mind paying for it?
Let's put the topic of assigning "disability" aside for a moment: An airline is a specialized travel service. Weight and size factor into everything on an aircraft - not just the passengers. I've seen luggage being tossed off because the aircraft was too heavy. I've been asked to change seats on an aircraft in order to more evenly distribute the weight - and I was 134 pounds at the time. If I weighted 184 then, I would have been insulted and felt discriminated against- but stilll asked to move all the same - because it wasn't about discrimination.
EVERYONE is restricted in how much luggage they bring and EVERYONE is charged extra for more pieces and if they're too heavy. Musicians must pay extra for another ticket if they choose to bring their instrument on board and put it in a seat and many do. The space you take up in the air is charged for by weight and cubic inch. There are so many restrictions in the air industry... we can't be too shocked and appalled when they don't always jump at the chance to accommodate passengers.
I always considered "comfort" to be something I give up when I fly - regardless of my weight. I give up a lot of regular "rights" and "freedoms" when I fly. So do all the passengers. If I want true comfort, I'd charter my own Lear.
I travel a lot and see passengers given extra space when extra space exists to be given. When it's not there, it's not there - period. If all the seats are filled, then all the seats are filled. What is the expectation here?
I'm just saying that accessibility is something that is easily arranged in some venues and more difficult to arrange in others. And what appears to be discrimination based on handicap or poor customer service isn't always so.
PS if anybody is going to jump all over me for this post, be sure you read the WHOLE thing first.