A mother and her 5-year-old son were flying Qantas from Sydney to
    Auckland.
The son (who had been looking out  the window) turned to      his
mother and asked, If  big dogs have baby dogs and big cats have     
baby cats, why don't big planes have baby  planes?"

The      mother, who couldn't think of an answer, told her son to ask
the flight      attendant.

So the  little guy walks up to the galley and asks      the flight
attendant, If big dogs have baby dogs, and  big cats have      baby
cats, why don't  big  planes have baby planes?"

The      flight  attendant responded, "Did your mother tell you to ask
me      that?"

The boy said, "Yes, she did.
   
"Well       then, please tell your mother that there are no baby
planes because Qantas      always pulls out on time - and ask her
explain that to you."