Increasing to 3x/week from December per this article:
Volaris inaugurates nonstop Portland-Guadalajara, Mexico service
http://www.bizjournals.com/portland/...o-take-on.html
"The Volaris service to-and-from Portland will run twice a week on Mondays and Saturdays until December 3, when it will add service on Wednesdays. The carrier said flights are available starting at $180."