Any air carrier that has entered into a signatory lease and operating agreement ("Signatory Agreement") with the City of Austin. I don't believe Alaska leases any space directly from the city. It subleases it's ticket counter & gate space from Delta.

Every month, AUS issues a Detailed Activity Report If you click on any month, then scroll down to the next to the last page, it breaks out the passenger count by airline. Alaska is always shown as "Alaska Airlines Inc. - Non-Signatory Operating Agreement."

Note that Alaska had 19,845 pax in November at AUS. Let's assume for a moment that 402Fanatic's data is correct and there are only 100 daily AUS-SJC passengers in each direction. Even if Alaska got every single AUS-SJC passenger, that would still only account for 6,000 passengers (3000 departing & 3000 arriving.)

That would mean the other 13,845 AS passengers were all flying to SEA and that number seems too high. 13,845 divided by 60 flights (30 to SEA & 30 from SEA) would be an average of 230.75 passengers per flight.

These numbers just don't add up.