Our daughter recently turned 2. Until now she has been doing her plane journeys on my lap. We are planning a trip to Italy in Sept. She has a separate seat booked, but I never thought of taking a car seat onboard until I read another thread in this forum. We are trying to keep our luggage to the minimum. Do all toddlers weighing less than 40lbs travel in car seats on airplanes? If so, that is one more thing for us to lug around!
I had same concerns for my son and called our Airline, this year it is Air France. They don't allow car seats for babies older than 2 years old. So we were told that if we bring one, then we have to keep the baby on our lap during takeoff, landing and turbulance, or we have to check it in.
So, we decided not to take one, since our driver for the transfers in Italy is providing one free of charge.
It depends on the airline policy and some allow them and other don't.