Originally Posted by channa

I don't believe this is correct. The flight is SOLD by Alaska, not MARKETED by Alaska. It's just an EI flight number on an 027 ticket. If it were a codeshare (marketed by Alaska), then your receipt would show both AS and EI flight numbers.

This is what an AS receipt looks like for a codeshare:

American
Flight 2834 (Alaska 4118)
Boeing 737-800

These receipts for the EI flights only show the EI flight numbers, which suggest they're NOT codeshares:

Aer Lingus
Flight 69
Airbus A330-300

Similarly, when you book online for something that's a codeshare, they display the operationg flight number, but the Details tell you whether a codeshare:

British Airways 284 (Alaska 5278)
Operated by British Airways

But these EI flights have no codeshare designation under Details:

Aer Lingus 60

So as long as AA doesn't care whose stock this is on, this is a regular revenue EI ticket sold on 027 stock. Question is if how they'll calculate the LP's.