My dear mother gave me her old kitchen table and chairs (can you tell that my parents are just itching for me to leave the house?
) and when I stuffed them into the Geo, only the table's legs could only fit in the hatch. The table top was sticking out with the hatch wide open, creating tons of drag.
It was late at night so I took the Trans Canada Highway back to my dad's house doing 35 mph. I couldn't believe it. I needed 0.7 GPH to keep the Geo in the 33-35mph range all the way home (around 50mpg at that speed) 0.7GPH got me into the high 45-48 mph range just hours before (around 65mpg).
Clearly aerodynamics play a big role even at low speeds since the table and chairs only weigh 100 pounds at most.