Secret Of The BMW Logo

BMW (Bayerische Motoren Werke AG — Bavarian Motor Works) logo represents white propeller blades against a blue sky. It reflects the origins of BMW as a manufacturer of the military aircraft engines.

The BMW logo might also have its blue and white cases because of its bavarian origin - the colors
of the bavarian flag are blue and white cases:

A lot of logos nowadays have just meaningless symbols, many designers forget that symbol should have meaning and background connected to the company (website, event, organization).