Those are aviation waypoints and airways. Waypoints are typically 5 letter codes, often meant to be pronounceable as words even if they're not real words. This site:
http://www.iflightplanner.com/AviationCharts/
will show waypoints in the US. If you take the portion of the flight that is over the US and plug it into the "flight route" field, it will show the path on the map. Try MERIT HFD PUT EBONY for example.