How to make loft follow guidelines on edge?

Hi there,

I'm trying to make an F-35, but have some issues with the front portion.

I've created a loft, and added guidelines using 3D fit splines which go from vertex to vertex. However, when I add this as a guideline to the loft, it doesn't touch the curve at all!

Additionally, when I pierce the curve, and connect a vertex to it, it doesn't actually intersect with the curve.

How do I fix these issues, so that the loft follows the guideline on the edge and make the pierce actually intersect the curve.

Thanks!