awrabbit, you can go to the Training Arena. It is enabled there.
While in the air or GV look at a friendly aircraft and hit ctrl + tab. This will lock onto him. Hitting tab again will switch targets that are in view. You can even look behind you and hi-light the guy on your six. This is usefull when practacing force oversoots and scissors.
Before you shoot anyone, ask if they will be you practice dummy. Or bring a friend so you both benifet.
You can also do it off-line with the drones, but they don't evaid well.
From the clipboard- click options, Arena Setup, Enviroment, and Arena Settings. Scroll to FlightModeFlags and dubble click on it. Check the Lead Computing Gunsight and Dive Bombsight(if you like) and click OK. Then press Save if you want it that way evey time you go in the offline game.
For enemy planes it Shift + Tab to enable and tab to switch targets.