Re: "Red Tails" Trailer
Well, "Memphis Bell" was made in 1990, during the last years of the optical FX age. There was only a small amount of actual aircraft they could film with. Today, with modern digital FX, we can fill the sky with realistic aircraft and show air battles at the actual size and scope that they took place at.
Moreover, all of that fire, explosions and smoke is simulated from fluid dynamics, so it's entirely CG vs filmed footage composited into the shot. Advances in fluid simulation have made all of this possible over the last 10 years or so, making the elements far better integrated and much more realistic overall.