Mom, if cats can have little cats, and dogs can have little dogs, why can't planes have little planes?

The mother, thinking for a second, and not coming up with a good answer tells the kid to ask the Southwest Airlines flight attendant.

So the kid walks up the the woman, and asks the same question.

The flight attendant asks if the kid's mother told him to ask her the question, and he of course responds yes.

The flight attendant, who is annoyed by having to answer such a stupid question responds:
"No, because Southwest always pulls out on time.  Now ask your mother to explain that to you!"