i used to think that but it's not REALLY the case...i mean in some places you technically can, but it will draw the attention of every single cop you see, and you might be arrested on suspicion of a crime you had no intention of committing...i mean, you'll probably get off depending on your state's laws, but it will be a really inconvenient day for you
in most cases states they also have laws geared toward prevent public hysteria, and open carry of a firearm is this sort of thing that makes people hysterical...i live in texas, and i never see anyone but cops doing open carry, but that's not to say it doesnt go down in more rural areas
here's a link that should answer every question about firearms and concealment laws:
ive double and triple cross-checked that site with state DA sites to make sure it's accurate, and it is
i spend most of my time in the central/rocky mountain corridor, and whenever im driving around it's usually in new mexico, texas, colorado, and wyoming. i do not have a CHL (concealed handgun license) because i had a misdemeanor beer charge my freshman year in high school, so i still have to wait another year (you have to be 5 years removed). HOWEVER, that site has taught me that all of the states i just listed allow you possess a firearm for personal protection in your automobile WITHOUT any sort of license as long as you're legally able to purchase a firearm and are not in commission of any crime above a class C misdemeanor while it's in your car.
so, naturally, any time im driving more than 30 or 45 minutes in any direction, i usually have my .357, i dont want to break down on the road and get ambushed by some "helpful" stranger while i wait for AAA, that just isn't how i want to go out...
oh, but remember, in most cases the SECOND you have one or two drinks it becomes illegal to have a gun in your car, so if youre going to do what i do, ALWAYS take the thing out before you go to the bars...and if you're not legal drinking age, most states i can think of say you can't own a pistol, so dont have one in your car if youre below 21 either...