There are lots of reasons people might not like flying...
Maybe you're afraid of what could happen in the air (even though study after study concludes flying is statistically much safer than driving).
Maybe you have a legitimate health concern that would prevent you from being at such a high altitude (there are a number of them!).
Maybe you don't like airline food (even though most airlines have stopped offering free - if any - meals in flight).
Maybe - just maybe - it's the prospect of encountering questionable behavior from fellow passengers while in-flight. There have been a surprising number of fights caught on camera... You could always find yourself surrounded by screaming babies... Or you could be a couple of rows behind this passenger - being forced to observe what is arguably some of the most repulsive airborne behavior every caught on video (I might be exaggerating a tad):