My late mother was a dreadful flyer.
At the gate dad and I would stand each side of her and literally push her down the airbridge (or up the steps). She always sat in the middle seat with dad in the aisle and me in the window seats (dad was significantly stronger than me, so able to stop her escaping into the aisle and running amok towards a door...any door)
She would grip both armrests or dad's arm til her fingers were blue and had been known to break armrests. Sat in her seat, eyes tightly shut, not speaking, not eating, not drinking til we landed and she was always 2nd off the plane (after dad).
We went on holidays once or twice a year and it was the same every single time.
The only time she was not too bad was aboard Tridents with the rear facing seats (she didn't completely relax but at least she didn't grip the seat or dad's arms so tightly) but any other aircraft she was a total nightmare.
Me, on the other hand, I tend to make others nervous cos I usually pass the time during flights by reading AAIB or NTSB reports...those sat beside me usually do a cursory look at what I am reading and their facial expression changes, the colour drops from their face, they swallow hard and look straight ahead for the rest of the flight.