>>10138549I think it was to catch those that missed the wire, IIRC they cut the engines entirely back in WW2 when they landed so going around for another try if you missed the wire probably wans't happening. May be a full parking lot at the front of the ship as well. Either way it was more of a universal than a Japanese thing. Nowadays missing the wire means going around for another try, and so the nets only go up if someone has a problem with the tailhook or for some reason simply can't take off again if they try landing.
