 These crossovers are revealed through characters' flashbacks, and are typically obvious only to viewers.Some intersections are quite noticeable, with different characters conversing with each other, but most often the characters are oblivious to these crossovers, which take the form of other characters' appearances on televisions or as glimpses in the background.The crossovers become more frequent in the final episodes of the first season, as all the characters approach each other before arriving at the airport, and finally board the airplane.