Zelna flew towards the top of the rocky mountain at full speed, which in this case was 35 km/h at most, or 21.7 mp/h.
She wasn't going to beat the speed of a Quetzalcoatlus Northropi (QT) anytime soon, or ever, but considering the fact that she could fly nearly as fast as she could run, her speed was nothing short of beneficial, if not impressive. She made it to the enemy in less than an hour, and even crossed the QT riders along the way.
The QT riders were spooked when they saw a flying human, but Zelna had done the smart thing and kept her distance from them. The QTs weren't hostile towards humans, not unless provoked or 'sicked' but if she collided with them her skeleton would turn into mush.
She kept her distance, and simply scared the riders shitless for a moment. They couldn't make out who flew past them, but considering what Jimmy achieved tonight, they simply assumed that he got one of the humans to fly. They didn't see Zelna as an enemy, thankfully, and let her be.
