There is also the risk of a toddler jumping up and running around during taxi. If you can't control your toddler during this crucial phase of the flight, the whole family can be off-loaded for "non-cooperation with crew member instructions". This rule existed before 9/11 but is much more seriously enforced since. If any passenger got up during taxi, we were required to call the cockpit who would then stop the whole aircraft. I had to do this a couple of times for pressing personal reasons. If it happens several times during taxi, you may find yourselves being brought back to the gate and "off-loaded". If you read any of these stories in the press, they usually happen during this critical time, while taxiing to the runway. Possible solutions discussed in another section...
Some parents justify not bringing a car seat because their tot doesn't "love" sitting in it. Mine didn't love theirs' either and this is really not a valid reason to not bring it. You are NOT required to keep your child strapped in for the entire flight but for the two, most-critical stages; take-off and landing, your child is safe. Flying with a lap baby is to save money so just be honest!
In the cabin is also the best way for your car seat to reach your destination. No risk that it will be banged around or damaged by baggage handlers or fall off the conveyer belt. No risk that it will be sent to the wrong city, especially if you need the car seat right away to leave the airport after arrival.
Absolutely never check a car seat as luggage!!! There are too many risk factors. If you are flying with a lap baby and can't get an extra place on board to use your car seat in, then gate-check it. This is no guarantee but better than checking it at the counter. Bring the car seat to the gate. This is not a problem if you're organized, and I'll help you with that in this article.
Sometimes when checked car seats don't arrive, the parents are conveniently offered whatever car seat is in their lost baggage section. Nice of them but car seat technicians warn against using any car seat that you don't know its "history". How old is it? Was it in an accident previously? Was is part of a recall? Has it been handled and taken care of properly?