i will say that in my experience, all pps are right, and all are wrong. IME, it compeletely depends on the flight crew and on-ground staff. I've been told that I bought the extra seat, one child (even though he wasn't sitting up - he was 3 months old) needed to be strapped in to the seatbelt when on the trip out, I was told that both babies needed to be held in my lap facing forward. I tried bringing on my Peg Prego infant seat, and it wouldn't fit in the seats - AT ALL. I've had helpful flight attendants, and those that want to know why I didn't bring my carseats for two twins, a singleton, and a dog - when I'm flying by myself - and THEN tell me that the flight attendant's union forbids them from helping to carry or install the carseats due to liability reasons. It has been a total crapshoot as to if the flight is peaceful or a disaster.
To the horror of many, I do not bring my carseats. I've seen the statistics, and for me, bringing the carseats is just not worth the hassle. The risk/benefit is just too low. I did bring it once (was shamed after reading so many posts here) and had to gate check it anyway. I have a greater chance of backing over my children with my car getting out of my driveway than turbulance severe enough to kill them. And when was the last US plane crash? And if you're going to nurse your children, either they or you will be out of the carseats/seatbelts, and there goes the "unexpected turbulance" benefit of the carseats.
Now that behavior profiling is being rolled out, I just want to get through the airport, to the plane and on my way. I don't want to have to fight any regulations, prove any points, bring any FAA-issued materials lest I get pulled off the fight as a risk. I argued with the flight attendant about my not-yet-sitting child not being safe and she pulled the "FAA regulations require passengers comply with all crew member instructions" cra* on me. So fine, whatever.
We fly all the time. Some flights are good. Some are bad. But nothing has ever been so bad as to keep me from flying. I think attitude and flexibility make all the difference. Think the trip is going to be a nightmere, worry about it for months, and watch it turn out to be a nightmere. Go with the 'whatever happens, happens' attitude, and probably not so bad. And I did get some good stories out of the deal.
Like the time my 5 month old had a blow-out, up the back, in the hair, poopy diaper. In the bording area. As we were about to be the last ones on the plane. I flipped him on the floor, whipped off his sleeper/diaper/onesie, wiped him up, tossed everything into a ziploc bag (the one my wipes came in! Yes, I had to use my ENTIRE supply of wipes) and tossed it in the trash. And made it on the plane with the door closed behind me.
Sorry to make this a novel. I just got home from flying today. After a 4 hour delay, 3 gate changes, and 3 tired, cranky kids. And am already thinking about flying again for Thanksgiving.
Good luck with your trip!