Having come across them in Japan many times, they can get as big as 10 cm across. Slightly less than a hand, but still extremely distressing when you run face-first into one.
Why do I keep reading the comments on this story?
I'm booking a one way trip to the North Pole or wherever these flying spiders aren't.
Looks like we're both signing up for the first one-way trip to Mars.
Some jerk is going to bring spiders and it will turn out that they're perfectly adapted to the Martian environment and it will just become the spider planet.
Somehow I made it all the way here before processing, how huge this thing is