Cutting to the punch line, Repairing a photo means, to me, fixing the scrapes and scratches so the photo looks like the only thing affecting it is time. Restoration, to me, means returning the photo to the original appearance, as if time has had no effect on it. This may be a distinction without a difference to many.
In this sequence I'm showing off a repair that took about 22 hrs. to complete mainly because the areas that were scratched included lots of detail on the CH-47. I used a wide selection of the Photoshop tools that would patch, replace and/or smooth parts of the image. Most frequently used were the clone stamp and spot healing brush. I even cut and pasted pieces of photos of other CH-47s and used blend modes to add to their authenticity.
The chopper pictured is "Easy Money" one of three "Guns A-Go-Go" CH-47s that were gunned up and used as troop support gunships for a short time in Vietnam. I happened to be at the pad while the crew was reloading the weapons.