I never really understood a situation like this:

American Airlines Flight AA86 from ORD to LHR $840.50 per way
-and-
American Airlines Flight AA86 from ORD to LHR
Lufthansa Airlines Flight 6731 from LHR to DUB $216.20


My company won't pay for a non-stop to LHR, and I really don't want to stop over in DUB on the way there. (AA92 from ORD to DUB then Aer Lingus 158 from DUB to LHR for $292.70).

I know that the 2nd flight is throw-away ticketing. I am an EXP on AA so I can get my upgrade, but will they cancel my return if I book the outbound flight and book a return non-stop on AA or a different airline? My company is getting really strict on their travel policies, and we really fought with them to let them keep our own miles and not use them for business use.

Now combining those two flights (the AA86 throwaway and on the way back a non stop for $670 on Aer Lingus) would be about $890, roundtrip on AA would be $1746, or a really cheap option on AA inbound/Swiss Outbound for $605 r/t.

I know there's different seating inventory codes and a set number for each one but I wouldn't think they'd be sold out already for mid-March.


And another situation......
UA634 ORD to EWR
UA635 EWR to ORD Total Roundtrip $177.10
-or-
US6412 ORD to EWR (Operated as UA634...same flight as above)
US6415 EWR to ORD (Operated as UA635...same flight as above)
Total Roundtrip $447.10

Who is dumb enough to choose the US-branded on when UA is wayyy cheaper? I don't understand those codeshares between them.