Re: flying with a 3mo old?
You could box the car seat up, if you want. Someone who worked at an airline told me that checking the seat when you check in is a bit better, actually, and she always had her own daughter do it that way. When they gate check things, they all get tossed down a slide thing on top of each other so she believed it was actually harder on the seat. There's no perfect answer, but I would consider boxing it up rather than dragging it through the airport if you're nervous about it. I haven't been on a flight recently that had extra seats, so I wouldn't count on that although I know it happens :-/