That's actually not correct. Some Android updates are OTA, but many are not. US Cellular puts out their updates over the internet, for the most part, which requires you to download the installer. The easiest way to update if you're not really familiar with these things is to take your phone in to a local USCC shop and have them update it.
For what it's worth, the newest firmware available on the Aviator is FG04, a build of Gingerbread (2.3), which is found in the "About phone" section of the menu under "baseband version." If you have that, then you're on the newest version.