Agree with a caveat. We know KB's phone "pinged" in ID, we know KK(L) is involved w/PF per friends in media, and know KK lives in ID.What? We have a deceased female and an arrested suspect with a known associate with the victim's phone that took at least one trip. These are the facts of the case.
It is logical that KK had KB's phone, but we don't know that, unless I'm missing something.
KB earned her Commercial Pilot Certifications 9/22/2015 and her Flight Instructor Certificate 4/24/2017.
She would have gotten pregnant around Jan 2017.
So you may be correct in your theory-- she could have been training for her flight instructor Certificate during her early pregnancy when she was living with her friend.
ETA: But she was already living in Woodland Park in March 2016 based on other interviews so perhaps KB moved to WP in 2016, moved in with friend temporarily in 2017 only to do Flight Instructor Certification then moved back to WP? Or KB was in WP the entire time and friend moved in with KB temporarily? MOO.
Link to look up KB's FAA certifications: FAA Registry - Airmen - AirmenInquiry - Name Search
Does anyone know how long it takes to earn a Flight Instructor Certification for Single Engine Airplanes?