Airbrush mode is an option for any normal brush now. I'm not quite sure what you're saying about the otehr stuff. This is solely dependent on your settings and whether or not PS recognizes your tablet. If it doesn't work, update your tablet driver.
The tablet works fine. Amd I can sort of get the effect I'm wanting by just making very short strokes and letting off the pressure at the end of the stroke. However, It's hard to do such s small stroke this way (maybe 3/32" long). Hence it would be easier if I could set the fade to do this for me. This version simply has way too many controls. I can't figure how to set it whether brush or airbrush. I've read done stuff about "size jitter" jitter this jitter that etc but non of it is helpful.
Yes, you might want to set, in Brush settings, shape dynamics the size jitter to 0 (the jitter makes the size vary randomly during painting, that's not what you want), but set its control to "fade" instead of "pen pressure", and set it to 10, or something that gives you the desired fading effect.
I don't use a tablet, just a mouse, but this used to be easy to do years ago and was a feature I used often. However, subsequent versions of Photoshop have to my eyes made this not just harder to use, but harder to find. Today I have spent hours trying to find a way into this having recently upgraded from CS3 to the latest rental model.
I finally found it more by chance than anything. Here is a screenshot with my settings – I hope it is of help to someone. To test it for yourself, just choose a basic brush, turn the airbrush option on top left of the menu bar, try these settings. My fade is set to 500 – this what controls the length of the brush stroke and therefore how noticeable the fade is. Keep on eye on the preview panel and watch it change as you alter that setting. Finally, when you have what you want, save it as a preset to avoid the pain when you can't remember what you did!