If you're trying to save money on your next trip, you've probably heard this advice: “Book your flights on Tuesday.” But is Tuesday actually the cheapest day to book flights? Not necessarily. According to Expedia's 2026 flight data, Friday was the cheapest day to book, with fares around 3% cheaper than booking on Sunday. However, other historical flight data shows that the day you book usually matters much less than when you actually fly. So if you're waiting until Tuesday ju
