Towards the end of season 2, episode 21 of Log Horizon, as Minori and the rest of the gang are walking home after getting some wyvern skins, they run into Nyanta, who "happens" to be flying by on a griffon. In the next scene, everybody is back in Akiba.
But how did they get back? Don't griffons only have a capacity of 2 riders? Did Nyanta make multiple trips, maybe?