- like the graph I showed
The graph you showed isn't flat.
You are making a mistake by looking at the portion of the graph where angle of attack is close to zero, this is NOT the place where typical flying happens (doesn't matter if it is Boeing or small Cessna), look at angle of attack around 5 deg, these are typical values and graph is no longer flat. Makes me think your are either non pilot or you missed some basic course of aeronautical knowledge. Also there are other better graphs which show this part of the curve in greater detail, you can actually find the exact graph for say Cessna 172.
http://www.aerospaceweb.org/question...rag-cessna.gif