I agree.

After living abroad I'm always startled at all the obese people I see when I return to the US.

It's mostly due to growth hormones given beef cattle, GMOs, pesticides, etc. in the conventional food supply. My slender, healthy, Thai friends tell me they also suddenly gain a lot of weight whenever they visit the US, but quickly lose it when they return to Thailand, and the natural Thai food.

Yep

Yes. You pay for the space you occupy. And if the flight is fully booked but someone paid for one seat and is taking up two, someone else either ends up standing, which is absurdly unsafe, or put on another flight, possibly fucking up their entire schedule. They cram as many people as possible into every plane and schedule transfers right on top of one another as it is.