
Proof lies in these images.
I was asked to illustrate two examples of Class B (bravo) airspace. One was to be a standard Class B airspace, like that above Cleveland (above), while the other was to be the maze of Class B airspace that blankets the New York City area (below).

Upon getting the assignment, I wrestled with different ways to present the airspace. Airspace being a "3D" sort of thing, you'd think 3D graphics would be the perfect way to represent it. But in fact, showing an airspace in 3D does little more than reaffirm what pilots-in-training know well: Airspace navigation can be complex! If you think it looks confusing in these images, imagine trying to navigate it when it's entirely invisible in the sky around you, and represented on navigational charts only in two dimensions.
The green arrows in the images depict paths that are free for general aviation (GA) pilots to use at any altitude without permission. Orange arrows show areas that are free at certain altitudes only. Red indicates where GA pilots may not go without ATC clearance. (For the record, GA pilots can (and do) reverse Class B airspace (the "blue" areas) all the time--we just need ATC clearance to do so.)