A few years ago, it used to be easier to find this answer. But nowadays it’s increasingly harder. I know that they used to do SJC to Burbank or LAX in turboprop, as well as between Spokane and Seattle or Boise to Seattle or somewhere in California or Portland.
Is the new Alaska airlines route between LAX and Mammoth lakes done in turboprop?
Alaska Airlines posts their complete timetable in PDF format. You can also see specific routes. Both include aircraft type.
The PDF timetable uses IATA aircraft codes, of which a table can be found here among other places.
Flights between LAX and MMH are shown with code DH8, which refers to the De Havilland Canada DHC-8 Dash 8 series of turboprops. In the specific route schedule this is shown as Q-400, referring to the model within this series which Horizon operates. So the answer to your specific question is yes, flights on this route are operated with turboprops.
