It is a good point though. Flats would be more comfortable, equally formal, and provide better support during turbulence. Wearing 1 inch heels for a longer flight would definitely start to hurt. It's not really sexism, it's just a stupid standard that flight attendants have.
Being a tradwife seems great if you chose it. My (soon to be ex-)BF has been telling me he doesn't think women should go to school or work jobs, even though I told him I would still be a stay at home wife, after I finished school.