A few years ago I switched from UA to AA because of their treatment of infants and kids. UA was deliberately avoiding pre-boards, etc. to discourage families from flying them and going after the biz traveller (Several press articles exposed this strategy). I was one of those biz traveller with an FF family.

At least now, I find UA and others have learnt their lesson and do not treat families as pariahs. I patronize all major airlines now and I do find that they chase after my dollars anyway and gladly welcome my FF kids, infants in FC and all