Originally Posted by
aindfan
My experience is that the blue line appears for what the website thinks is a stop instead of a connection, and it can be wrong. It will definitely appear between flights where you turn around, for example, between an LAX-HNL and HNL-LAX. However, when I had an LAX-HNL (5 hour stop) HNL-SFO, I didn't get a blue line. Also, the computer attempted to check me in for every segment until the next blue line.
By the way, I had a fare break between LAX-HNL and HNL-SFO, but still no blue line.
There are lots of things wrong with the itinerary display on united.com. Blue line is simply what the website thinks when the next set of flights, in this case the next day. However, it has nothing to do with fare construction/connection, since you can technically connect within 24 hours on an international itinerary.