Made a wingbone from a bird I had killed and went to the woods and used nothing but that call and killed a nice mature Tom. Sat there in stunned silence not believing that actually worked as I was anything but good on it at that point. Thought it was a fluke and yet went back on a different day and tree yelped one off the roost and shot him. I suddenly knew I was on to something. That was five to six years ago and I am still trying to perfect my craft with those air drawn tools.
But to respond to the initial post - it is just an awesome instrument that the Native American Indians used many years ago to get food for survival, and I dig that. Even better it is when you make the call with your own hands. If you master a trumpet/wingbone - you can take that call and maybe a scratch box or a purr pot and a diaphragm to the woods and that not only really simplifies things, it cuts an awful lot of weight from the vest/satchel if you are having to do a lot of walking/climbing as some us are having to do.
You can get an air drawn call right now and go kill a bird with it next season - it can be done. However, to be fair to anyone thinking of embarking on this journey, I think you need to think at least 3-5 years to really become proficient on one to the point that you have no hesitation to pull it out in the woods and use it during the heat of battle. The Rev. Farmer said that it took him several decades to master his calling. Mr. Profit said it took him 8-10 years. Regardless, with an air drawn call - think marathon and not a sprint. And soft calling is the secret sauce!