OK, I've been reading this for years but have never posted. Now I am stumped and don't know where to go for answers. We booked a flight from LHR to LAX via Continental in Business Class and tried to upgrade on miles. Continental said it was not possible as this was a code share flight operated by United. So, being a member of UA FF program as well, we tried to upgrade through them. Again, not possible because this is a code share flight. Is this all BS? Thanks.

You'll probably get a more definitive answer on the Continental or UA forums, but it is pretty normal not to be able to upgrade codeshare flights.

New to Flyer Talk. Can someone take a minute and explain code share? Thanks!

Unfortunately, this is correct. If you had booked the flight using a UA flight number, you could have upgraded the flight using UA miles. But you cannot use CO miles to upgrade a UA flight and you cannot use UA miles to upgrade a flight booked with a CO flight number, even though it is UA metal.

From the airline's point of of view, the economics of a direct sell vs a codeshare sell are quite different - hence, different rules about using miles on a codeshare flight.


To TimeZone - a codeshare flight is one in which one airline buys seats on another airline's flight and puts its own flight number on that flight. In this case, CO purchased seats on a UA flight and resold those seats with its own flight number. Thus, the same flight has both a UA flight number and a CO flight number and one can purchase a ticket from either airline using either flight number.

This is done for numerous reasons but basically it comes down to a joint marketing effort between the airlines that theoretically gives more flexibility to the passenger and thus makes these flights more "sell-able" for the airlines.

Yup.

CO would allow you to upgrade a UA-coded, CO-operated flight using CO points but not using UA points. UA doesn't allow advance upgrades on any of their flights that are purchased under a different carrier's code.

Thanks for the explanation JerrFF!! Very helpful.

Upgrading a UA code-share on LH metal with a UA SWU (must be converted to a paper SWU) is possible on a stand-by basis.