[MichaelSalib]

I forgot to add: the buggy data issue is exacerbated by poor engineering practices common in the airline world. Imagine you were designing a format to describe flight schedule data. How do you represent a flight segment temporally? I'd probably use two numbers: A GMT departure datetime and a duration. Instead, airlines specify a local datetime for departure and another for arrival. So now, in addition to all the fun that comes from handling local times, you've also introduced a whole new category of data errors: I've actually seen carriers file schedules for flights that arrived before they departed (i.e., when you convert the departure and arrival times to GMT, the departure comes after the arrival).