fly-by utility

I'm looking for a utility that, like active camera pro, will allow me to watch external fly-bys but that won't make the tower view inaccessible. also, the more control over the flybys the better. also also, something that will allow me to set the starting point for the spot plane (so that it will travel a long distance before coming alongside my plane)anybody know of any programs that will do some or all of these things?thanks in advance.-andy