If you have ever heard the sounds of an airplane or jet above you and wondered what it was, there is a cool app that maps and details most civilian and some military flight info.  The app is free and can be found here: https://globe.adsbexchange.com/

By pressing the "U" button at the top you can filter out civilian aircraft and look at only military flights. At least the ones they allow you to see. There is a ton of functionality to this app I have not even discovered yet, but it is fun to play with to see what is flying overhead in my neck of the woods, or elsewhere in the world. 

Give it a whirl for yourself, it is pretty fun. It is also insane to think about all the planes in the air at any given time of the day or night and all the humans who are floating above us at any given moment. ;-)