Babies want nothing more than to sit on your lap snoozing and feeding. It's more or less what you do at home anyway. The hardest part about flying with a baby is dealing with the added luggage (stroller, carseat, overpacked diaper bag, etc).

It's only once they're old enough to have more sophisticated feelings (like boredom) but not old enough to communicate them (except by screaming) you get in trouble.

First two years they can fly for free, but they have to ride in an adult’s lap and that gets tiring. Don’t believe the bassinet offerings - as soon as a plane gets turbulence, you have to get the sleeping baby out of the wall bassinet and good luck appeasing them. Age 1-2 is hardest for travel, so you can skip it. The only thing that worked was getting their own seat with the cosco scenera next car seat (or their own if they like it, but that one is $50 and light to carry). They would sleep nicely for large chunks and you get to enjoy travel again. After age 3 it’s much easier (they can ipad if that’s the only ipad time they ever get).