As it pertains to flying, hypnotherapy helps you overcome the destructive thought patterns and so-called “Thinking traps” which cause you to dread the very notion of setting foot on an airplane. Intellectually, you know your fears are baseless. You said as much in your OP. So why do you still feel this way? The reason is because you’re the victim of a set of destrutive thought patterns which you have adopted and internalised to the point where they’ve become deeply ingrained in your unconscious. Here’s an example. You know that aeroplanes are fantastically complicated pieces of machinery. In all likelihood you, like most people, probably haven’t the foggiest idea how they actually work, right? God knows, I certainly don’t. So there you are, suspended 40,000 feet in the air, encased in several million dollars of what might as well be alien technology when you hear a strange sound emanating from one of the engines. Now, you probably have some preconceived idea of how things which work are supposed to sound. When your car makes a funny noise, it’s a sign that something’s wrong. You take it to a mechanic, and receive a bill for services rendered. The bill also itemises several repairs which you never even suspected were necesary. The lesson is learned. When something starts kicking out weird noises for no reason, chances are good that not only is something seriously wrong, but that, whatever it is, it’s only the tip of the iceberg! So you start freaking out. There’s a problem with the engine. You’re doomed. Smoke 'em if you got 'em 'cuz you’re going down.
That kind of thinking is typical of the sort of destructive thought patterns which so bedevil anxious flyers. Hypnotherapy is all about providing you with positive thought patterns with which to counter the negative ones. The induction of a trance state is useful because it allows for the suggestion of these positive patterns to be absorbed unconsciously, which makes them more effective. Incidentally, the concept of the “trance” is one which has been grossly misrepresented in the media. Hypnotic induction isn’t something that’s done to you. It’s something you do to yourself, with the hypnotist’s help. It’s all about getting you into a relaxed frame of mind where you can attain a greater level of focus than you would be able to do otherwise. You remain completely in control at all times.
A positive thought pattern typically comprises facts which run counter to the negative patterns. Such as the fact that you have no idea how a plane works and are absurdly unqualified to judge which noises are normal and which aren’t. Or that aeroplanes are subject to rigorous safety checks after every flight, and that the aviation industry as a whole is absolutely obsessed with safety. Alternatively, a positive thought pattern may emphasise the pleasant and enjoyable things about flying, such as the gorgeous views, the presence of a wide range of entertainment facilities, or the fact that you’re sharing a space wih several hundred people taking advantage of a technology which would have seemed like high witchcraft 150 years ago. And let’s not even get started on the tempting range of foods and beverages awaiting your purchase from the refreshments trolley. The unconscious adoption of thought patterns like these allows you to step aboard the flight with a completely different attitude. These positive patterns are also self-reinforcing, and get stronger with every safe, successful, and utterly uneventful flight that you take.
There is, I believe, a peculiar law of mental conservation which states that one cannot hold two contradictory ideas at the same time. Since, during hypnotherapy, the positive thought patterns are adopted at an unconscious level, and since they are so pleasant to hold, they will easily overwrite the uncomfortable negative thought patterns, leaving you wondering what all the fuss was about in the first place.
Also, while under hypnosis, the unconscious is more prone to suggestion. That means the hypnotist can induce you to recall positive thought patterns at strategic points throughout the flight. For instance, the hypnotist may suggest you think about how much fun you had on your first ever flight (since you alluded, in your OP, to the fact that you used to be a very good flier, I assume you must have enjoyed your first flight) when you see the drinks trolley. Or she may suggest that the decor of the typical 747 is, for some unaccountable reason, particularly relaxing to you. Or something like that.
I’m not going to say that hypnosis is a magic bullet. Everyone’s different, and who knows, maybe I’m just particularly susceptible? I will say, however, that my experience was so positive, that I feel comfortable urging any nervous flyers to at least give it a whirl. What have you got to lose?