Of all the recent games that try to portray small-arms combat in a semi-realistic fassion, CS is one of the furthest from reality. That’s like saying you can learn great millitary tactics from Starcraft (Unless your idea of “great tactics” is just to swarm them with overwhelming numbers)
And while the controlls for a flight sim (Joystick, throttle, rudder, etc) are fairly similar to a real-world craft, a mouse is in no way a substitute for a firearm’s grip. Besides, all the “realistic” FPS games take rather large liberties with reality to make an “interesting and fun” game, while flight sims try to stay as true to reality as possible. Big difference.