The state of Illinois has control over the transport of ammunition and firearms. Non-residence may carry a concealed weapon in their car if they can legally do so in their home state. An FOID card is not required for non-residence that have a permit to own a firearm in their home state.
Public Act 098-0063: Firearm Concealed Carry Act
What is Peaceable Journey?
A nick name for the FOPA law. It is a federal law upheld by most (but not all) states. Peaceable journey allows a gun owner to travel through states where they do not have a license to carry, without fear of being arrested. Most states require the firearm be unloaded, in a locked box, or out of the driver's reach when they are in the vehicle. In some states the drivers must pass through the state without stopping, and in others only short stops are tolerated.