about little airplanes

A boy and his mom are riding on an airplane. The boy asks his mom,

"Mommy, if big dogs make little dogs, and big kitties make little kitties, why don't big airplanes make little airplanes?".

His mom replied,

"I don't know, honey. Why don't you go ask the stewardess!"

So the little boy scampered up the aisle and approached the stewardess. She said,

"Hi, little boy, what can I do for you?".

The boy said

"If big doggies make little doggies, and big kitties make little kitties, why don't big airplanes make little airplanes?".

The stewardess smiled and said,

"Did your mommy tell you to come ask me that?"

and the boy nodded.

The stewardess bent down and looked the kid straight in the eyes. She said,

"Well, you can go tell your mommy that the reason our big airplanes don't make little airplanes is because Continental® planes always pull out on time!"

"Now have you mommy explain that!"