Are Heated Driveways Worth the Cost?
If the state requires a contractor's license, then he needs to have a license in each state he intends to work in - plus state/local business licenses as applicable.
This does not mean there are not a lot of contractors who cross state lines without proper licensing - the penalties in may cases are not real severe and are just a fine, not criminal, so many take the chance.
As you say - argh - many contractors are not really businessmen and have zero legal education, so many people get burned.
To overlay,with proper adhesion so it does not peel off, you first need to prepare the surface - typically heavy watercutting or sandblasting for concrete over concrete, or high-pressure presure washing and an asphalt (NOT water based cutback) adhesion coat before asphalt overlay.
Because of the prep cost, a concrete overlay commonly costs more than just tearingit out and replacing it, and if you are replacing it due to cracking and breaking up those cracks will almost always propogate or "reflect" through the new layer too with concrete. Ditto with asphalt overlay, though using a crack-stopper fabric can reduce (but usually not eliminate) that.
If just repairing ice melt/freeze thaw deterioration, a cementatious epoxy overlay can be used, though its life is less (normally) than new concrete. Usually used for limited areas like garage area pad, not entire driveways.
Asphalt overlays over somewhat deteriorated concrete can work well,but if not prepared and high-pressure (about 5000 psi or higher) cleaned to remove ALL deteriorated material, they can peel off because they stuck to deteriorated loose material rather than sound concrete. Again, can cost as much for a 1-1/2 to 2 inch overlay as for a 3-4 inch full replacement by the time you are done, because the prep work is labor intensive.
Even if this is just a surficial deterioration issue, I would talk to several contractors (site visit) about alternatives and let them bid both an overlay and a replacement (or whichever options they are inclined to bid on), then after getting opinions from all three and bids for all options, make your decision. I am pretty confident that total replacement will be both the most recommended and the cheapest, at probably about $2-4/SF for asphalt or 4-6/SF for concrete - commonly nearer the lower than higher range for most jobs and locales. If the overlay and replacement cost is pretty close,I would go with the replacement because overlays over concrete are always somewhat iffy as to how long they will last, especially concrete overlays.
For cost comparison, except in extreme freeze-thaw country, you can figure a concrete drive will last about twice as long as an asphalt one.