Just a follow up to The_Banking_Scot's reply; from the US CX also flies from ORD to HKG. However, I really can't help with which airline has the best schedule to HKG from ATL. If you do opt to fly CX TAPC, then your domestic flights will be with AA (thier US based partner airline). As ATL to HKG is a long flight you will earn lots of miles, so plan wisely based on your current status (if any) and how you could use the miles earned for future travel.