Originally Posted by
samjnz
If you're flying in on United you can just check in for both flights at your first departure (even if on different tickets) -- just ask them to "through check my bags".
Usually they get a little confused working it out on their system but make sure you have your Air NZ ticket number handy (not just your booking reference).
It's worth bring up the topic of interlining bags. There are other airlines out there (not just *A carriers) that will interline bags with Air NZ and I have done this on multiple occasions with flights via LAX. Pre Covid (and I have no idea is this policy still applies so it's very much do your own due diligence first) AC, AS, DL and UA were all capable of doing this as they all have interline/codeshare agreements with Air NZ for North American connections. Sometimes getting this done does rely on finding check-in staff who have the knowledge and understanding to do this.
The key thing is just make sure you then remember to give the bag tag # to Air NZ checkin at LAX (or whatever airport you're flying through) or your bags simply won't get loaded onto the Air NZ flight.