For real, what are these white strings/filaments falling from the sky?

There are tons today, it hangs everywhere it is unbearable, my radio-controlled glider is fully covered with white wires after 10 minutes of flying!
They explain to me that these are webs of very small spiders, but I do not see any spiders hanging on them (and why spiders would flight at 20-300 ft??) and the appearance is a little different from the spider webs, a little "plastic" and less fibrous