All you have to do to get priority boarding because of a disability is to ask. If you then board early (at least on SWA) you can’t sit in an exit row. They will not (can’t) ask what your disability is.
The ADA doesn’t apply in Canada so Canada can set their own rules about doctor documentation about weight being a disability to get the free extra seat but I’d be pretty mad if I were 6’6" and not getting an accommodation.
As in planning…
to fly days early, on the exact same planes, but now pay for extra overnight stays & meals, lose extra days of work - and only if you are a certain body size?
I agree to disagree with you, that airlines should be permitted to force this upon a certain subset of our population by making seats already too uncomfortable for many of us - rather than having to “cost average” that across all their customers.
Completely off-topic but they do in some cultures/religions.
Cost average means the price goes up for ALL customers to satisfy that subset.
My position is that the DoT (Mayor Pete?)/Congress need to address this, as a safety issue, and they have chosen not to. And if the Feds don’t want to wade into the fray, the airlines can choose to make their customers more (or less comfortable) for the price point.
Yet somehow they are allowed to use averages where it benefits them, by keeping my overpayment when I don’t fill the space between two arm rests, my feet don’t reach the floor, or my lightweight costs them less fuel?
In reality, very few pay our exact personal “cost” - we already pay “averages”. You’re just chosing to exclude some people.
I have only made it to this post in this thread so perhaps there has been follow-up…
First, your post made me laugh, especially about the manspreading, until I saw the quote above. Surely that’s a joke. I cannot imagine and shudder thinking of it. Many, many years ago I was traveling while on prescription meds that made me drowsy and awoke at the announcement to prepare for landing to find myself leaning on the shoulder of the passenger next to me… a kindly gentleman who just went with it, but a complete stranger nonetheless. I was mortified and disgusted for him and me! And I was in a window seat so there was really no excuse.
I don’t want anyone uninvited invading my personal space and no way in h-e-double hockey sticks am I voluntarily encroaching on a stranger’s… for my own well-being and comfort level. Excuse me while shivers run up and down my spine at the thought.
American Airlines Policy for Plus-Size Travelers | Portly Passengers American airlines says ya gotta pay for 2 seats
From that link, American Airlines’ definition of customer who should buy the extra seat requires both overflow at least 1" beyond the armrest and a seat belt extender.
If my head is within the boundaries of my seat/backrest/headrest but my neighbor is so far into that space, resting against them is a default. Where else should one go? I often use one of those neck pillows that wraps around your shoulder area. If my seat mate is so close that that thing is one them…what should one do/
If that neighbor happens to be spreading on purpose…(in my world middle seat gets both arm rests but doesn’t get to put their elbow into my ribs, feet into my foot space or shoulders into setback area. Also in my world - window seat controls the shade) then resting a head or shoulder against that body isn’t a choice its’ physics.
The very last thing I would do anywhere is rest my head against some stranger’s body…just wouldn’t do that.
I don’t fly all that often, but when I do, I expect that I will have my full seat to myself.
If someone is so close I could put my head on their shoulder without much effort I’m DEFINITELY not sleeping!
(This thread is just reinforcing my proclivity to stay home and not travel unless necessary. 
I’m a happy, content introvert, and became remarkably more so during Covid years.
Thankfully, hubby is on same page. We appreciate our home and our dogs.
Our kids can travel. And we will enjoy viewing others’ photos of such……but I love my house, pool, yard, and very quiet neighborhood quite a bit. Throw in books and kindle and I’m set.)
The only truly disgusting/horrible flight I have ever suffered through was a SWA flight to Las Vegas. I don’t currently have the stomach to recount the experience, but if I ever fly SWA again, I will never sit trapped in a window seat again. Those 4 hours were truly miserable to suffer through.
Wait a minute. Sounds like you are much more comfortable than I am since I take up most the width of my seat, and certainly the entire seat pitch on a standard seat, whereas you have plenty of room. I think you should be paying more. 
Actually, we are not paying for the average weight or size. We are paying for the max passenger weight and size that a seat can handle. While the airline has to spend a bit more fuel on a heavier person, that extra 50-100 lbs of a large person that the seat can still hold is dwarfed by the roughly 145,000 pounds empty weight of an airplane like a 737 MAX.
In other words, the per-passenger variable cost is small whereas the per-passenger additional revenue is large. And so the revenue and profit of a plane is largely dependent upon how many passengers it can hold, and does hold.
The seat size that an airline chooses is based upon maximizing the number of passengers it can fit without alienating too many. Spirit has alienated me due to its seat pitch, but the business model works for them. But according to you, I should be able to demand that they give me more legroom for free.
I used to hate flying (understatement). I had some nightmarish days flying with babies, toddlers, and preschoolers when we lived across the country from family. Now that we are older and have the means, we pay for Comfort plus or business. If we’re flying for vacation, I would chose not to go if we couldn’t afford premium seats. Coach is just that uncomfortable and stressful, and I am not a big person.
With a bigger seat and an ounce of privacy, I’m so much calmer. If we sit on the runway for a couple hours, I don’t mind. I actually look forward to the flight as a time with no demands on me. But sitting in coach for a long flight is an exercise in grim forbearance.
As for people of size, I feel for them. If I hate the tiny seat experience so much, how must they feel with all the added judgement and shame?
I am hoping that the new weight loss drugs will help many, and also change our warped perception of weight. It’s just a genetic lottery, which the new weight loss drugs show. The drugs mimic our natural GLP-1 satiety hormone, which suppresses appetite. Thin people naturally have more of this or react more strongly to it. It’s near impossible, in a food rich environment, to fight against hunger all the time. If you try, it can take over your life, causing poor mental health and even eating disorders.
I do not have much trouble maintaining a healthy weight. I do exercise, but for mental and physical health, not weight control (exercise doesn’t work well for weight control, especially alone). My sister did not win the genetic lottery on this. She exercises twice as much as I do (runs marathons) but still, if she wants to avoid overweight, she has to restrict herself severely. She can’t just restrict herself to healthy food, she has to go hungry, often. It’s vastly unfair.
I think we will make these drugs better and better, and eventually offer many different doses. People like my sister could take just enough to stop being so hungry, and stop having to count every calorie. Someone who doesn’t have the time and expense it takes to be a health-nut like my sister could take a higher dose, etc.
I don’t feel superior to my sister or anyone who has a weight problem. We are all doing the best we can with the hand we were dealt. I am grateful that we can use medication to fight back against our genetics, and against the addictive high sugar/high fat foods which flood our markets.
Completely off topic to airplane seating, but ^^^ not true. To maintain a healthy weight, exercise certainly “works well.”
And genes aren’t one’s destiny. Human behavior (diet and exercise) tends to be the culprit for being overweight.
Generally, the problem is lack of commitment and improper diet and exercise methodology. My apologies for digression.
To me, the topic has a lot to do with whether being overweight is a choice, or mostly genetic. What you believe about that affects your approach toward the problem.
Exercise makes many people hungrier, and the amount needed per day is prohibitive. We evolved in situations where it was advantageous to overeat when food was abundant. Now, food is always abundant. Most people are wired to eat more than they need to maintain weight, and to conserve energy by moving less. It is very difficult/near impossible to overcome without help unless you are genetically lucky.
I think that the conversation about weight loss can be moved to it’s own place.
Here’s the latest. An plus sized influencer says that other passengers should in effect subsidize the extra seats required by the plus sized.
The comments after the article are interesting.