He is using QWEASDYX buttons to have full control about his plane with his left hand.
You are right. Exactly the same buttons.
However that still doesn't explain the speed you had. It was just redicuolous in several situations.
My speed can be easely explained if you know some basics of air combat.
From the school we know two kinds of energy: kinetic and potential. Kinetic energy is an energy of movement, potetial energy is an energy of position. Applying this to plane, we can say that kinteic energy is presented by speed, and potential one is by altitude. There is also a gravity force that always accelerate a body. If your plane goes up, the acceleration is negative. If plane goes down, the acceleration is positive.
That's a simple theory that works in real life air combat.
Now how it works in SAMP. You may have noticed that I often do vertical manuevers. When I go down I always get additional speed from gravity force. That's why I'm faster than you (you don't usually do vertical maneuvrs). Look at the video I posted before. Starting from 0:32, when I took you down, I have a another pilot on my tail. I need to shake him off, but I don't have enough energy to do this. I smoothly go up, gaining a potentional energy and then sharply go down, converting my altitude to speed.
I was taught this method by this guy:
http://www.youtube.com/user/ThePspilot . He's the best rustler pilot I ever seen. Nobody (including me) could beat him. His videos was very helpful to me in terms of understaing ruslter dogfight. So It will helpful for you.