I would guess it dates from the 1950's as most of the brochures were from that same time. Printed on the back is "My Creed" by Dean Alfange. Alfange was and American politician who ran under numerous parties. He penned "My Creed" for This Week magazine in the 1950's.
Flying W suffered a devastating loss in 2012 when it was overrun by the Waldo Canyon wildfire (sounds like someone missed out on this handout).
Here's an interview with the 87-year-old (in 2012) owner just after the fire.
Their website is still active and there is hopeful speculation they will reopen for business this summer. I hope they do.