This is something I would also like to know, as I have a modest interest in airplanes and have always wanted to build an combat flight simulator game with simple physics. Something similar to Ace Combat (a playstation and xbox game). Same as Nuno, I've encountered problems understanding all the complex math and integrals.

As to how you integrate in Pascal, I think you don't. Integrals are used to reach the end formula. I extremely suck at these though I studied them at college.