Wow, a post full of hatred towards large people but also slim people with then obligatory LCC bashing thrown in This place never ceases to surprise. Mind my troll-o-meter just gave me a master caution when I read this post.
Do you have such a venomous attitude toward PRMs?
If the certain LCC was Ryanair, the minimum height is 5'2".
The fashion these days may be questionale these days but compared to the days of the highly flammable shell suits, I don't think there's a significant risk. Certainly no more than 6 inch heels that people criple themselves with these days.
If you dread the cheap and cheerful airlines then its a free market. Don't fly with them.