International Airline Connections?

ANA and United are Star Alliance partners and have interline baggage and ticketing agreements, you should receive all your boarding pes for your outbound flight and have your luggage checked through to Bangkok when you first check-in in Kansas City. The same applies on your inbound flight, except that you'll need to clear customs at your first point of entry in the US and retrieve your luggage to do so. You then can drop your luggage off at a counter for connectiong pengers.