I'm stuck on doing what seems to be a simple process but can't for the life of me work out how:

I am building the fuselage of an aircraft in halves by drawing 4 curves at key points along the hull (nose, 2 middle, and rear). I then selected all 4 and lofted them to create my surface, which did what I wanted.
Now all I want to do is duplicate, mirror and attach to complete it.
Ideally what I want to do is use the Mirror Geometry command, but it won't let me because it isn't a polygon.
I've tried duplicating and rotating, but I can't do that because it needs to be reversed.
THERE MUST BE AN EASIER WAY!!!
I've attached a jpeg of what I have so far. Any help on this will be immensely appreciated.
SiriusMark