Depends on how the gun is carried, and what type of gun. You need to give us some information to get a meaningful answer. Every 18 yr old that goes deer hunting "carries" a gun in their vehicle.
You will have define the term "carry a gun". If you mean as a concealed weapon, no. You must be 21 to be issued a permit.
Yes
Yes
yes your car is an extension of your home
If you can legally own a gun, you can carry in Alaska. See related link for more information.
Yes, you can carry a gun in your car in Oklahoma. However, it can not be loaded, and it must be kept in a case with all or at least part of the case visible.
In PA you have to be 21 to conceal carry (or carry loaded in your car) a handgun.
If you carry a gun you can stop car jacking.
Yes, it is called Open Carry- although there are places you may not carry any firearm- schools, post offices, courthouse, etc.
Yes
Yes/ no with these conditions. A legal possession of a gun in Washington is 18 years old. A minor has to provide a hunters license or hunter's safety certificate with a shotgun. A minor engaged in hunting may carry a firearm as long as the gun is unloaded and not accessible in the car.
You vcan carry any type of a firearm in Kentucky as long as it is not concealed. There are no laws against carrying fire arms. Of course you will probably have to sue several police departments, but that is also possible.