The air speed indicator in a plane has a red line called "Never Exceed Speed", for some reason unclear to me. Before that is a yellow region. I forget what it is in a Cessna 172, something like 160 knots I think. You can't reach that in level flight. The indicator stops at 40 knots on the other end, it is possible to fly below 40, but at full power oddly enough, you cant the attitude up and basically hang on the propeller. Needless to say your flight controls are mushy at such a low speed, and it's pretty easy to find yourself in a stall situation (which is easily recoverable).
It's not that hard to get a private license, it is some effort and expense of course, but I do marvel at these fellows who fly F-16s in combat situations with so much going on.
P.S. I looked it up, NE speed is 182 kt in a 172.