We have a 6.5 hour driving commute between where we live now and our family farm and my wife hates flying. We had a terrible experience in a Turbo Prop Commuter over Texas once where the turbulence was so bad that the flight attendant went airborne, landed on the seat back, breaking her ribs. Then the pilot made an emergency landing with an initial rapid decent. My wife flew home after that and didn't set foot on another plane for several years. I ended up getting my license without her even knowing. The one thing that peaked her interest was watching youtube videos about Angel Flights and vacations to remote places to fish, ride horses, etc. I would watch a video every now and then while she was in the room. It just takes time and there's not much you can do unless she develops an interest on her own.