I had a similar experience and delivered a similar fear. I wasn't afraid of being dead, I was afraid of dying and the emotional pain that would occur as the plane falls from the sky (or whatever). Like you, I knew rationally how unfounded this is. I've been getting more comfortable with flying by accident since my bad flight experience.
Two things, the first being rationalization, the second being more immediate:
1. I read that a plane has never crashed from turbulence. If somehow this is not true HN audience, please don't inform me otherwise. A crash every X million miles or flights isn't that concrete for some reason, but "never" makes me less scared some turbulence is going to knock the wings off. Along the same vein, I think the last US commercial passenger crash was in 2009. That's more concrete than the statistics. Nine years since the last crash. Pretty good.
2. I got a prescription for some benzodiazapenes for flying. I was stuck in some kind of feedback loop, where I was initially kind of scared of flying, there'd be some minor turbulence, which would make me freak out, which would be unpleasant and give me additional anxiety about flying. White-knuckling a flight for however many hours is unpleasant enough to fear itself. Also, my primary fear was the same of yours, I was afraid of feeling afraid as I was dying. Taking the benzo made me think, "if I'm drugged maybe the descent won't be so bad," which helped acutely, and over time it made me have more tolerable flight experiences. After flying three or four times without a fear in the world I forgot my benzos and found that my fear of flying now still exists, but can be rationalized away much better than before. Unless you fly multiple times a week, drugging yourself through the experience isn't generally a bad idea. Flying sucks so much even without fear that it's kind of a preferable way to go anyway.