I was reading a Popular Mechanics in a waiting room, and they had an article
on how to fix a flat.

They said that tire repairs involved putting a patch on the inside of the
tire. That is how mine were fixed in the past, but the last few have had
plugs put in. The plugs seemed to work fine. What is the proper method.

They also recommended a can of air and material to plug the hole for
temporary repairs, and then getting a real patch. I was told that those
cans ruin the inside surface so a patch can't be used. What is the story
there?