If you buy a Honda, you are probably buying American because most Hondas sold in the US are actually made in the US. For that matter, you can also buy Toyotas, BMW, Mercedes, and other "foreign" cars made in the US.
Plenty of "American" cars by GM, Ford, or Jeep/Chrysler are actually made in Mexico or Canada, China (Buick Envision), Italy, or have a substantial percentage of foreign-made parts. Jeep/Chrysler (FCA) is actually an Italian company, so if you buy a Jeep Wrangler, the car is made in Toledo, Ohio, but the real company headquarters is in Turin, Italy. If you buy a Jeep Renegade, it's actually built in Italy despite all of the Jeep heritage marketing and imagery.
So you really need to define what you mean by "American" because the term is very ambiguous. Do you mean 100% from an American factory? Sold by an American-headquartered company? Sold by the American subsidiary of a foreign company (FCA)?
Also, when you look at percentage of "American" content, "American" also includes "Canadian" because cross-border manufacturing was so integrated with the former Big 3.
It's a big can of worms.