Your rational mind knows the facts. You know airplanes are built to handle turbulence and that pilots deal with it every day. Still, that doesn't help much, because fear lives in a different part of your system. Your nervous system reacts faster than you can think. A bump, a strange noise or a change in the engine sound, and your body braces itself before your mind can form an opinion about it.
After that, a loop often starts. You feel your heart beating faster, you notice it, and that makes you even more afraid. You start looking for confirmation: do the flight attendants look relaxed, did I hear something weird, how much longer is this going to take? The more you watch for signs of danger, the more of them you find. That isn't you being dramatic. It's your body doing its very best to protect you, just at the wrong moment.
For many people, the lead-up is harder than the flight itself. The images start weeks in advance. You put off booking, look for the shortest route or end up taking the car after all. That's how your subconscious learns that flying is dangerous, because why else would you avoid it? Avoiding it feels like relief, but in the long run it makes the fear bigger.
Every person already has the ability to trust without managing everything themselves. You get on a train without knowing the engineer. You sleep in a house someone else built. So that trust is already there, just not on the airplane. In hypnosis, you make that connection. That's how you learn to let go of control in a place where you couldn't before.