Airplane Metaphor

Dr. Horn believes that a family with a mother and a father in a healthy marriage is compared to an airplane that always reaches its destination, and a family with a single parent is compared to a plane that only sometimes reaches its destination.  To me, this is a very opinionated and awkward metaphor to use to express this idea.  First of all I don't really think that there are some planes that are more unreliable than others or "sometimes" reach their destination, because those are the planes that have crashed and are no longer functional at all.  Dr. Horn then goes on to say that everyone would choose the first plane, and in the context of planes of course they would, but I am sure there are many people who are more than satisfied with being raised by  single parent.  I really think that what depends more on the success of a child is how it is parented rather than who or how many people are parenting them.  I know many people who have parents with a healthy marriage, but fail when it comes to parenting .  It all depends on how you go about raising your child.