Sounds like you are doing things right and it could just take more time. Keep in mind that the bird may not like being touched/handled like that. It doesn't mean we can't train them to overcome that (for instance zoos and aquariums teach their animals to voluntarily allow blood samples to be taken), but since it is unpleasant, their natural desire is to flee it. This means that either you better stop doing it or make it sooo rewarding that the reward outweighs the discomfort.
There are two ways to make the reward outweigh the discomfort. First of all, make the discomfort requirements much much less. For example, the bird does not like wing opened. Well, don't even touch the wing. Just hover your hand 6 inches away without touching. If this makes the bird fly away, try 12 inches next time. If it does work, hold it there for a little bit and then reward by giving food and taking the hand away. Then work your way closer and closer. Sneak a touch in. Apply more and more pressure and/or increase duration as it gets better.
The second aspect is to up the reward. Make sure the bird is reasonably hungry and that the treats are worth enduring being handled for. Once you can break past the trust and touch barrier, things will get much better. Eventually the bird will learn to enjoy beak and head scratches so it will gladly let you do them. But until it knows that it's a good thing, you will have to use these taming techniques.
Be happy that the parrot flies away. Sure beats biting. And it is clearly telling you its limits. Practice by staying just at or below those limits and slowly trick the bird into pushing those limits a little more and a little more until you achieve your goal. Here are some articles that help illustrate the points:
http://TrainedParrot.com/Taminghttp://trainedparrot.com/index.php?bid= ... New+Parrothttp://trainedparrot.com/index.php?bid= ... ching+Beakhttp://trainedparrot.com/Toweling