I didn't buy a seat for LO and I'm not going to - let's get that out of the way.

I have been on flights that are not completely booked and they let her sit in the seat next to me. I can't find the padded case we use to check our car seat (we are in the middle of moving and I don't know which end is up). I'm traveling with our cheaper seat but I obviously am concerned about the safety of it getting banged around and then using it for the weekend once we are at our destination.

If the flight is not fully booked do you think they will let me bring the seat on and use it?