I will consider contact $3$--manifolds $(M,\xi)$ that are also total spaces of fibrations with a two-dimensional base $F$, so that the fibers are Legendrian with respect to $\xi$. A Legendrian knot $K$ in $M$ then has a front projection to $F$. I will show how, for a fixed base $F$ with standard constant curvature metric, $M=ST^*F$ (the bundle of cooriented contact elements to $F$) and $K$, one can vary the fibration so that the resulting family of projections is a wave propagation. I will also prove that if the fiber is a circle, then $M$ is a covering space of $PT^*F$, the bundle of contact elements to $F$.