He uses a Digitech Whammy, on the Octave up setting, as well as a 1970's Big Muff he has custom made. The boost comes from the MXR Micro amp, as others have stated. This is then run through a Fender Twin Reverb, and a Silvertone head. Not sure of the model. F-28 or something springs to mind. Either way, it's from the sixties and very fragile. He's criticised sometimes for having everything turned up to full volume. This combined with his spasticated picking technique, is what gives him the choppy, interrupted, solo sound. He also uses upstrokes almost exclusively, and the heavier the pick, the better. Lightweight strings, but he doesn't tend to know, or care, what strings are on the guitar. He leaves it up to the tech. In regards to the Airline, the one he used most had only one working bridge pickup. The pickups are single coil P-90s in humbucker casings, as was the trend with Airlines from that era.