[Stiglr]

More on that intake...

On second glance, you might consider redoing that whole area to get better results.

If you can, get back to a solid fuse nose without the intake aperture. Or a fuse half, if that's what you were working with.

Use the Knife tool, along with a rectangle shape as the Knife, to accurately describe the aperture or aperture half. Combine any odd surfaces around and in the intake, such that the aperture or aperture half is one surface.

Then select that surface and extrude it into the fuselage. If it's a straight chute inside, one operation will do. If it's got a lip or a bevel, try Indent on the surface first (multiple times for a very rounded lip), and then Extrude the remaining inner surface inward. Cap the inside if you need to, or leave it uncapped to save polys.