One trick for handling that is to start with a cube, and then use Vertex > Smooth Shape to round the cube off until you have something roughly sphere-shaped to start.
A better way, however, is to use a cube or cylinder to build a single slice of the shape, then extrude in either direction to get the rest of the shape. If you keep your cube very low poly (maybe three or four slices, max) then it will become very smooth\round when you turn subdivisions on, especially if you crank up the subdivision level all the way.
For something like your airplane fuselage, I'd start at the thickest part and build a ring representing just that slice. Once you're happy with it, grab the surfaces and extude forward and to the rear to build each additional slice.
Here's a quick video showing what I mean:
http://www.independentdeveloper.com/files/plane.wmv