When talking about Grand Theft Auto III's development, Rockstar VP Dan Houser revealed that a lot of the changes they needed to make to the game after 9/11 were primarily cosmetic and not as grand as everyone thought they were.
Fans believed that Rockstar had to take out a ton of content in order to show respect to those who had died or lost someone that day including characters amd missions. Houser denied those rumours saying that only a few things were altered after 9/11.
The team changed the color of the cop cars since the original color scheme was similar to the NYPD cop cars. They also changed the flight plans of the airplanes floating around the game so they would never fly around or into skyscrapers. Only one mission was removed, because it revolved around terrorists.
Grand Theft Auto III is celebrating its 10th anniversary this year and will be coming out on the iPhone and iPad 2.