Here's a thought experiment. What would happen if you were on the International Space Station, folded up a paper airplane, and threw it from the station? According to a new paper, it would fall from orbit in just 3.5 days, but still keep aerodynamic stability until about 120 km. Then it would heat up and combust at about 90-110 km altitude. It's a fun idea, but there are actual practical uses to probe the density of the atmosphere or test thin-film space technologies.