[ETL]

Actually, now that you reminded me, there is a slight amount of air at that altitude which does create a minor amount of drag, particularly when the atmosphere swells during moments of increased solar activity. In fact, they need to fire its on-board boosters in order to increase its altitude during these times. Otherwise it would be going too slow to remain in orbit at that particular altitude. However, at no point here is it ever "flying". Do you think it uses its solar panels as "wings"?

[ETL]

“This plot [see chart at link] shows the orbital height of the ISS over the last year. Clearly visible are the re-boosts which suddenly increase the height, and the gradual decay in between. The height is averaged over one orbit, and the gradual decrease is caused by atmospheric drag.

As can be seen from the plot, the rate of descent is not constant and this variation is caused by changes in the density of the tenuous outer atmosphere due mainly to solar activity.”

http://heavens-above.com/IssHeight.aspx?lat=40.7759&lng=-73.9677&loc=Unspecified&alt=21&tz=EST