No way did you get that bad mileage at 60mph.
I think that you actually got much better than 26mpg. What happened is that the previous renter filled the tank up, then drove another twenty or thirty miles before returning it. The gas guage still read full but the tank was down about a gallon.
WAY.
I checked it on the way down there....filled it up.....and checked it when I returned it.
Maybe I just had a bad car? I am renting another "economy car" from Enterprise on the 6th of october so I hope its not the EXACT same Aveo that I had before.