In Flight Simulator 2004
Using the drop down menus, select the following:
Aircraft Manufacturer: Commercial Level Simulations
In Flight Simulator X
Using the drop down menus across the top of the screen, select the following:
Aircraft Manufacturer: CLS/Just Flight
Publisher: Commercial Level Simulations
Please ensure that you have the "show all variations" box ticked at the bottom of the aircraft selection menu to see all of the variants and liveries available.