re: domestic travel w/ 3 month old

0-6 months is probably the easiest to fly with. Be sure to have extra formula and water (if you formula feed) as you never know when to expect a delay on the tarmac. Do not get caught without a way to feed that baby, for everyone's sake on board.

I flew on 25 flights with mine from 1.5 months old to 1 year old. Every now and then we had a cry/freak out moment but it can almost always be solved with food or the boob.

As others have said - gate check your stroller, I would actually wear my baby through security and to the gate, then on to board and to deplane and walk to baggage. So I had my hands free the entire time and baby was comfy.

When they are old enough to eat - bring all the food and snacks (yes, it all gets past security). After they hit a year - best of luck until they can focus on an ipad around 2. Those are some tough times!!