Ok so I know how to add flights useing airplans and ttools, but when I try to use a helicopter it never works.
I had the same problem and received some advice that eventually got it running. You have to modify the airfile from an aircraft, to take the place of your helicopter airfile (and which can be a real project as extensive mods will have to be made). You can also look for the Schweitzer AI helo. Not sure where I found it, but it is freeware and works "out of the box". Only thing is, upon taxiing, it does so like a normal aircraft, and looks pretty funny driving around on it's skids.
Flight Sim Questions that are closely related to this...