Airplane restrictions
Hi..
I have dealt with this situation as well. I had bottles of prepared formula confiscated at security in the US, and I have had unopened, sealed water confiscated even with a baby in my arms.
What I have been able to get through are the sealed cans of prepared formula,(are these available in HK?) and of course the powder mixes. I have had luck both with coffee places giving me warm water, and just using lukewarm water on the planes.
My daughter has also been okay with water from a bottle. After about 12 months, it seemed she was comforted more by the bottle than what was in it. You might also try the UHT milk in small sealed containers if your child can have that yet. I have never had a problem bringing baby food on board either.
Good luck and happy travels!