Not quite sure what you mean here; AOL has been on Windows since before it owned Netscape. I believe that Netscape is an end-of-life product, and that they aren't developing it anymore. Back in the (mid-late 90's) time when I was still using AOL, you didn't have to use or install another browser at all, as the browser was integrated into the AOL core client.
Before they released W/98 Gates told Case, the only way AOL would be on the W/98 install disks is if he dropped the Netscape option when you installed AOL software. (that happened at aol 3.0 as I recall) Case caved in and removed the netscape (or any other browser) option. AOL software got buggy after that. When I run AOL I am using IE even though my default browser is Firefox.
Netscape became an end of life product because of this. If AOL, the owner, can't use Netscape on their own product, how much future can it have. This is just another case of Microsoft squeezing superior technology out of the market with their wallet.