Miaka - Your choice might be made easier by what is actually in stock in HK, unless you are thinking of buying one elsewhere and bringing it back to HK as we did.
When I checked at Bumps to Babes a few months ago, there were only 2 car seats that could be used on the plane because all of the others needed a shoulder belt to secure them. We didn't realise this when we bought a Britax car seat when our baby was born. We then had to buy another car seat to take on the plane which could be secured with a lap belt.
You'll want to to check the user manual or speak to a salesperson to make sure that the model you are interested in can actually be used on the plane. Probably not all of the car seats on the NHTSA list can be used on the plane.
When I checked at Bumps to Babes a few months ago, there were only 2 car seats that could be used on the plane because all of the others needed a shoulder belt to secure them. We didn't realise this when we bought a Britax car seat when our baby was born. We then had to buy another car seat to take on the plane which could be secured with a lap belt.
You'll want to to check the user manual or speak to a salesperson to make sure that the model you are interested in can actually be used on the plane. Probably not all of the car seats on the NHTSA list can be used on the plane.