The thing is, there used to be very few airline stewards but a lot of stewardesses. Back in those ancient days when jet travel was an upper-class thing the airline stewardesses were supposed to be pretty girls. And no, I don't think the word "stewardess" implied any high status. Great lord's estate or no, a steward is still a servant (Gondor notwithstanding).

The change to "flight attendant", IMHO, was done to eliminate the gender reference.