M.N.
S. A.
I have to agree with Jennifer N.
The car-seat is really the safest way to fly with your child.
The only exception I would consider is if your child is in a sling. For some reason, when you sling your baby, flight attendants leave the mom's alone, but if you use a "Baby Bjorn" or any carrier such, they will not let you hold your baby within because they are not FAA certified. When you lap your baby and there is an unfortunate even, your baby is not safe--I know everyone has seen the pictures and videos.
When my son was a baby we lapped him once and it was not fun.
My son was not happy. All the other times we flew we used his seat and the trip was pleasant, he felt safe, his seat was his security--and our sanity. He has always been placed by the window, though. That shows a difference in flight attendances and airlines. Basically in a nut shell, what is the age of your child?? Can he/she be snuggled safely in a sling, or will he/she sit still in a seat. At age 3 1//2 my son, gets harder and harder to sit still without his car seat.
The car seat might be a pain to carry around the airport, but the safety of the child is the most important.
If you still want to check it at the gate, yes you can, they will tag it just like they will tag your stroller. Oh, and that is the easy way to carry the car-seat, turn it upside down over the front side of the stroller, then sling the baby.
The other alternative, if baby is in stroller, is strap car-seat over stroller handle-bars.
Good Luck, M. N.