Rhamphorhynchus
It can be interpreted like this. To dart about quickly requires special advanced brains and reflexes to keep control. Later birds and pterosaurs had extra 'control wiring' in their brains, but early ones did not. The evidence for this is the extra size of pterodactyl and bird brains compared with the reptile brains the groups started out with. That much of this increase is connected to seeing and flying is clear from how bird brains work.