If you want some fantastic WW1 action, get
Combat Flight Simulator 3 and you can download the
Over Flanders Fields mod free online. You'll probably hate CFS3 standalone, but you'll love OFF. Graphic wise, IL2 graphics will pummel the graphics from OFF, but it's still pretty good. Here's the OFF teaser movie. You might like it:
http://www.polovski.com/off/Movies/OFF-MOVIE1.wmv
Otherwise MS2004 might get boring if you're not one of "those" people. You know, flight-sim nut...
And Age of Empires II: AOK is really old. Avoid it at all costs.