Traveling to the US soon? Don't forget to pack the your passport, and check in to your flight online. And check if your flight is delayed using your flight number. Speaking of, how the hell do aeroplanes come up with flight numbers? Apparently there's a system! Like did you know flights that go east or north are usually given even numbers while west and south flights have odd flight numbers.
MentalFloss decided to crack the mystery of US flight numbers (they aren't just random lottery picks) and found a few patterns. Along with the odd and even distinction, return flights on troundtrip tickets are given a number one higher/lower than the original flight. Also, the lower the number (we're talking single or double digit flight numbers), the more money it makes for the aeroplane.
Four-digit flight numbers bring a whole 'nother set of rules like different airlines running particular flights purchased from another airline. It's pretty confusing. There are always exception to the "rules" of flight numbers but in general, they can stay the same forever. Read more about it here. [Mental Floss]
Image Credit: AP