What is the purpose of the open panel just below the cheatline towards the front of the fuselage? I used to think this was some kind of access panel that was closed prior to takeoff, but after seeing many a plane leave the gate with it still in the same position, I've decided that it must be something else.
Also, what about the little fins and the one big fin on top of the fuselage? Do they serve as transmitters of some kind or are they just there for aerodynamic reasons?
Here's the photo I'm referring too:
Click for large version
Photo © Brian Hames