A boy and his mother are about to board a Cathay Pacific Airlines flight. The boy suddenly asks his mother: "Mum, if dogs have baby dogs and birds have baby birds, why don't planes have baby planes?"
The mother tries to shrug off an answer and says: "We need to board now. Please ask me later again."

Finally in flight the boy suddenly remembers his question again and again asks: "Mum, if dogs have baby dogs and birds have baby birds, why don't planes have baby planes?"
Obviously bothered to answer her child, the mother answers: "Why don't you ask the stewardess?"

Taking his mother's advise, the boy walks up to the next flight attendant: "Excuse me, miss!"
The stewardess politely replies: "How can I help you?"
The boy asks his question: "Can you explain to me why dogs have baby dogs and birds have baby birds, but why don't planes have baby planes?"
Surprised by this question the stewardess asks: "Did your mum tell you to come to me and ask me?"
"Yes" the boy replied.

"Well," the stewardess starts "go back to your mum and tell her it's because Cathay Pacific always pulls out in time."