Hi, Krisakira...hugs for you and anyone else who struggles with weight problems of any kind. I, too, suffer from hypothyroidism, which has made me steadily gain a worrisome amount of weight over the last ten years. It took me damn near forever to get a doctor to even listen to me and help with it, at all.
And I would be horrified if anyone, no matter where, made an issue of my weight because the idiotic airline designers cannot get it through their heads that we are all different sizes.
And, as QII said, there may be rude, self-absorbed infantile minds out there---but that is "on them"---they own it---not you. And you musn't let their behaviour diminish you, or who you are and how you feel, at all.
MOST people are very nice and are polite in public situations. I hope you have a very pleasant trip, and have good, kind, and thoughtful travel companions.