Orbitz, CheapTickets … Who Copied Whom?
Note the similar layout, same search results, same wording, same abbreviations, same pretty much everything, except the colors, theme, and a few minor layout differences. The results are so similar, it appears they may be using even the same database. One notable difference in the search results is that Orbitz returns 250 results, whereas CheapTickets returns 150. But in both cases it could be an arbitrary cutoff.