Originally Posted by
Indelaware
The important difference here is that ZK is a non-*A
partner unlike the UAX
operators like OO. Other partners include 9K, HA, and EI.
Keep in mind that, unlike many other partners, you have to book the UA codeshare to get ZK credit. To complicate matters further, the UA codeshares can only be purchased as part of a connection. If you buy a ticket directly from ZK or via a travel agent and it carries the ZK code you cannot get UA credit. For example, UA245 (ORD-DEN) connecting to UA7302 (DEN-LBL) gets credit whereas ZK7302 (DEN-LBL) does not UA7302 cannot be purchased without a connecting UA flight.
This is different than, for example, NZ where you can buy a ticket directly from NZ without any UA segments and get credit.