[sp332]

You're allowed to discriminate against even "protected classes" of people if it actually materially affects their performance. If a woman is actually pregnant and can't lift heavy things, and that's part of the job requirement, then you're allowed to not hire her. If a heavy passenger is actually costing you more money for fuel, you'd be allowed to charge that person more for fuel. This is moot though, since height and weight are not protected categories and you can already discriminate against them all you want!