The DC-8 was the first commercial aircraft out of Hawaii (to LA) in March 1960. They later added the 707 in Sept 1960. Both had a service ceiling altitude in the mid-30s (not that great to avoid turbulence). Also, 36,000' (DC-8 service ceiling) translates into 8,000-9,000' pressurized cabin altitude.
Ever flown with an infant? They can't clear their own ears from the change in pressurization. Nursing or bottle feeding may help, but there's no guarantees, and I can't see Ann being that savvy with babies and airline travel.
Ever change a diaper in an aircraft? It's not fun in a B-747 -- it sure as hell would not be a hoot for an 18-year-old girl to change a diaper on a DC-8 or 707 going to LA from Hawaii.
The bus ride from LA to Seattle wouldn't be a joy ride either ...
Travel from Seattle to Hawaii when she supposedly was enrolled in college in Seattle would have been no small feat, either.