Maybe after this island they go to another island to spend the night at and its there that Ava says the next day he should probably take her back(or at least close) to her home village, stating her father would be back soon and he agrees in order to gt her to not argue with him for the time being and takes her to Berk and she realizes too late(like when they are about to land XD)
PS sorry if my writing/ideas are crappy right now haha XD Just had a log day at college and I am some what out of it.