Standard texture packages can be downloaded here

Airport design program:
Download here

VOD (Visual Object Designer by Rafael Sanchez) 3D object design program:
Download here

Airport and Scenery Designer (ASD):
Download here

These textures are used in practically every scenery package you download, and are a must have for any flight sim enthusiast who intends to add new scenery to the simulator.

Textures for Flight Simulator have come with various name extensions, like *.r8, *.oav, *.txr, *.tex. FS2000 is the first version of Microsoft Flight Simulator to be able to make use of standard Windows *.bmp textures.