Originally Posted by Eclipsepearl

The deciding factor is, do you need your car seat in S'pore or not? If you need it, you definitely want to bring it on board. Don't ever check a car seat as luggage (too many get broken and lost).

If you are bringing the seat, just use it for take-off and landing if your child does better sleeping flat. You could just put the car seat to the side or under the seat when reclined.