I've discovered an easy way to add cockpit to almost every plane in the game, exept for bombers that does not have one. In just 3 step!
step 1: google a snapshot of your favourite plane cockpit, possibly taken from the pilot seat, and save the image on your pc/mac/ps3/xbox..
step 2: print the shapshot on paper, making sure paper sheet width will fit your television screen size. If you've got a very big wide screen, split the prints in more parts and mosaic them using some glue or duct tape.
step 2.1: cuts the paper cockpit border with some scissors, removing unwanted blank paper parts, making sure not to cut your finger during the process.
step 3: apply the paper cockpit on the television screen, choosing a comfortable height ( i do not suggest you using glue for that, but, maybe some tape ), making sure it will cover part of the viewpoint and part of the television screen.
step 3.1: Start a game with your home made cockpit and have fun!
Drawbacks: Gauges probably would not work on your paper cockpit.