A license is a granted permission to engage in a business or occupation or an activity that is otherwise unlawful.
A permit is a written form of permission.
A privilege is a special advantage, an immunity, a permission, or a benefit granted to or enjoyed by a specific class of people.
We used to have the right to go anywhere within the territories and States at will. This right included whatever mode of travel we desired to use. This right has been relegated to a mere privilege. Right or wrong, we no longer have the right to travel by whatever means we desire.
Regardless. the Feds (the comity clause - Art IV sec 1) were never involved in the recognition of our vehicle registrations and drivers licenses. This was done solely at the state level, through reciprocity agreements. Sound familiar?
What may be needed, is for the various states to standardize concealed carry, such that moving from one state through another will not cause the bearer the grief of legal action against him. We are seeing some of this happening now, to a greater or lesser extent.
There is no need to get the feds involved. What you would get are all kinds of regulations and stipulations, just like what's in the recently passed law that federalizes concealed carry for active and retired LEOs.