"Can controls be released when viewing a film? "
You mean as in AW, where you can fly the filmed plane? No; you can't.
"Is there a way to organize films by folders?"
Not throught the AH interface. You can rename the files with explorer, but if you put them in a subfolder, AH won't find them.
"Trail" is best thought of as thin smoke trails from the wing tips..it helps visualise the A/C's path through the sky. It's very usefull to see how the A/C move, especialy in exterior view.