AZ Express
I believe their parent company is AEX in Arizona and is partnered with Air Desert Pacific (flight school) in California. AEX contracts with banks around Arizona to fly checks to/from Phoenix. AEX has a reputation of flyng junk into conditions they shouldn't be going. I think they also have been under the watchful eye of he FAA after they were caught operating beyond the scope of their certificate.
Yes, they are the ones at terminal two at Sky Harbor with the AZ flag paint scheme. Come to think of it I've never seen it move either.
If you really want to fly 1900s out west look into Great Lakes Airlines. They have a big hub in Denver an actually share a ticket counter with AZ Express. You would get better flight time flying from PHX to Page, AZ to Denver anyway and still have Part 121 Flight Crew jumpseat privledges.
Just a thought!