  It is shown that the single particle band motion along the $c$ axis is
harmful for superconductivity. Variation of $T_c$ with $c$ axis hopping
parameter is shown for both the conventional planar superconductors and for
interlayer pair tunneling mechanism of Wheatley Hsu and Anderson(WHA).Effect of
out of plane magnetic impurity substitution is shown to suppres $T_c$ more for
conventional superconductors whereas there is very sharp decrease of $T_c$ in
the WHA mechanism at larger concentrations.
