Is there a way to connect a standard joystick to the game for flying?

You should be able to go to the options - controls setup and click on the control you want to change, then move the input you want to map it to.

So if you want the Pitch down of the airplane to be a up on your flight stick, just click that box, press up on your joystick, and that should be it.

A lot of guys at work went out and bought flight sticks just for that purpose!