I realize that this had been bantered back and forth but I have to chime in on the always buying my child a seat/always using a car seat side.
I travel on a plane, and a car the same way... assuming that THIS is the trip where an emergency of some kind (crash, turbulance, etc.)...and if this is that trip, I'm going to secure my child(ren) so that they are the safest that they possibly can.
That means in the car I make sure that their harness straps are very tight and their seats are secure, on a plane that means that I purchase a seat for them (if under 2yo) and make sure they are in a car seat as long as they still fit into an FAA approved seat.
Am I a "better" parent..nope...just one that knows the risks involved and even though the risk is low on a plane... there is still a risk that I can mitigate by securing my child in a car seat. God forbid if there was an emergency where my child was injured (or worse) when using a seat would have protected them, and I didn't use one... I would NEVER be able to forgive myself.
So every trip we purchase a seat for our under 2yo child (we are on our second now!

) and every trip we use a car seat.
Dd (who is now 6yo and no longer needs a car seat on the plane) flew 5 times before she was 3.5yo and to be honest she slept on 9 out of 10 legs of our flights!
One of our flights to Orlando a family of four sat in front of us, mom, dad, dd ~4 and dd who was just under 2yo... as a lap child. They were MISERABLE the entire trip. The younger dd crawled all over them and both kids were whining/crying. The mom kept turning around looking at dd longingly as she slept for the majority of the trip.
So that is my long answer. We don't fly unless everyone has their own seat. If it came down to an emergency and we had to travel...I would give up something else or borrow $$... and still get a seat for my under 2yo child.