Consider the following premises. For all z, if z works, then z is taking a plane. There is at least one z for which if z takes a plane, then z is working. For all z, z will not work. Can we infer the following from them? For all z, z will take a plane.
 From the fact that for all z, if z works, then z is taking a plane, and that there is at least one z for which if z takes a plane, then z is working we can infer that there is at least one z for which z will work if and only if z will take a plane. Finally, from the fact that there is at least one z for which z will work if and only if z will take a plane, and that for all z, z will not work we can infer that there is at least one z for which z will not take a plane, which contradicts that For all z, z will take a plane. Therefore, the answer is no.