Quote Originally Posted by ach5 View Post
Im not sure why, but instinctively it feels odd that military aircraft are displayed on these trackers. I'd just have imagined that would be all secret?
Some are...some aren't. Some sites show them (when their transmissions are on and received), others don't...see ADS-B Exchange for:

First and foremost ADS-B Exchange does not participate in the filtering performed by most other flight tracking websites which do not share data on military or certain private aircraft. Because ADS-B Exchange does not use any FAA data there are no FAA BARR/LADD, military, or other “filters” preventing you from seeing the the data you collected. ADS-B Exchange simply does not accept payment or requests to remove aircraft from public tracking!