So basically, kitesurfing on a thread. Cool. I've seen flying spiders many times in Poland, and it was fun to watch. Especially because it's not a common knowledge they could do that.
It's both a name of the behavior and of that time of year.
I haven't really noticed that phenomenon in years though now that I live in a city, I wonder if these expressions will just eventually disappear once too few people live in the countryside.
Kites are lifting bodies. This is different physics.