Whenever he thought about it, he felt terrible. And so, at last, he came to a fateful decision. He decided not to think about it. ~John-Roger and Peter McWilliams
Question #25539 posted on 06/06/2006 3:01 a.m.
Q:

Dear 100 Hour Board,

Why do planes occaisionally make white streaks in the sky, and why doesn't it happen all the time?

- the pope

A: My Dearest Fellow Practitioner of Priestcraft,

These streaks are called contrails. A simple search on Wikipedia will answer all your questions.

-The Right Reverend Rusky Roo