commuting on Mesa aircraft
 

Do Mesa pilots have priority for the jump seat on Mesa aircraft ahead of all others, and what is their priority for other carriers. Also can you book the jumpseat in advance.

Yes priority on own metal. That's pretty much the case with every airline.
Priority on other carriers varies by that carriers policy.
No you cannot book it in advance.

If you want a picture of Mesa priority on ANY other airline, imagine competing for the last seat with a ramper’s ex-girlfriend’s Chihuahua and the dog smiling back at you as you watch the pushback from inside the terminal. That’s pretty much how it is ...