I used to be a flight attendant, but that was a) in the 90s pre 9/11, b) part-time and c) for the German Lufthansa. I had a friend who was with American Airlines and I know their schedules and training was somewhat different, so anything I tell you might not apply in America. However, I’ll try to give you an impression anyway, if you have any other questions, feel free to ask!
At first, we had to do a course regarding the emergency procedures which lasted a week. This ranged from learning where the fire extinguishers are stowed on board to actually trying out the emergency slides (fun! whee!!!). We had to do this for two different plane models (I was on the B737 and the Airbus 340, later I received additional training for the B747) - German law only allows flight attendants to be trained on two models. As far as I recall, my American friend received some sort of “basic” emergency training and then had something like a thick manual of all different types of aircraft she had to get acquainted with individually before every flight.
Then, we did a 3 week course regarding the service: How to stock your beverage trolley, how to prepare the cabin before take-off, how the service flow works (different on each aircraft depending on your position). We also did some courses about the wine and food on board and on how to apply make-up properly (I kid you not!). After that, I was qualified for economy and business class, first class required an additional course that only full-time employees did.
In addition, we had to do all sorts of health exams: measurement (one girl was fired because she had lied about her size on the application), weight, blood tests etc.
So, how did I like the work? I actually liked it fine (maybe that also had to do with the fact that I only did it for 2 months at a time). We had to do 80 flight hours a month - “flight hours” actually meaning “from take-off to landing”. That meant if you were doing short-range flights you were SOL because the actual air-time on those is rather short and you have to do a huge number, leaving little free time. I on the other hand was mostly scheduled for long-range flights. That meant I got to do 3 flights to the US a month, translating to about 10 work days, plus 5 days of “standby” time (where they get to call you if somebody calls in sick). The rest of the month was free, and actually lots of my colleagues pursued a second job (usually in the form of selling something like jewellery etc. because you get to meet lots of people in the job).
The work itself was rather meh, not very challenging intellectually. Think waitressing in a restaurant that’s usually very crowded, where people are more snappy than usual and you don’t get any tips. The gropey men did not happen to me overly much, I much more hated the annoying whiny “Why are you not as good as airline X” men or the Russians who would order about a thousand Vodkas and then sneak into the galley and steal your bottle if you weren’t looking. As an anecdote: When I worked on a flight to the US during the soccer World Cup (in the US) and Sweden were playing, economy class was filled with Swedish soccer fans. As Swedes are wont do, they imbibed quite a lot on-board (alcohol is very expensive in Sweden) and the whole economy class started singing soccer chants. Whereupon a business class traveller asked me to go back there and shut them up. Yeah. I’ll go back there and tell 200 completely drunk Swedes Mr. 54D doesn’t want them to sing anymore. (As to how drunk everybody was: When we had finally finished our debarking procedure (which takes quite long in the US, you have to prepare everything for customs) and we left the plane, we met some Swedes who had not found immigration yet and were wandering about the terminal - it was 1 hour later and if you know JFK: you can’t really miss immigration if you just go straight). But that’s the level of expectation you meet: you are responsible for everything that happens to the passenger.
But I liked the travelling, even if you did not have lots of free time, you did get some, which meant lots of sight-seeing for me! You also usually had nice colleagues - at Lufthansa they don’t have set crews but rotate everybody. This means you almost never met the same people twice, which had advantages (no cliques, no mobbing etc.) but also disadvantages (going through the same small talk all the time, not really having the time to establish relationships). However, most of them were very sociable and it was easy to find somebody to do things with at your destination.
The most negative factors were the physical factor and the social implications. Physically it was rather exhausting, what with the jet lag and the long hours and working on a plane while it swerves up and down and you get airsick. Also, if you look at older flight attendants, you know what the radiation up there does to your skin (and who knows what else). And socially, it was harder to maintain relationships with friends, because you never knew when you would be home (they could change your scheduling on a whim and you never had the same schedule twice in a row).
So all in all, I never regretted having worked there, but I don’t know if I would be saying the same thing if I was doing it to this day: As far as I know hours have gotten longer while pay has decreased, and I’m not as young and sprightly as I used to be, dealing with jet lag is getting progressively worse (judging from my business travels now). It’s fun to do for a few years but you should definitely keep your options open if you burn out or plain want to do something more with your brain than just asking “coffee or tea?” for the umpteenth time.