This form generates an iCalendar-format file describing travel from one place to another, paying particular attention to getting the timezones right.
For example, you say you're flying from "Seattle" in "United States", and it allows you to choose which American timezone that's in ("America/Los_Angeles" is the right answer here). And you're flying to "Wellington" in "New Zealand" (which automatically selects "Pacific/Auckland" as the timezone). Put in a date and a time for each, and it generates an iCal-formatted file for an appointment called "Seattle to Wellington" that you can import into your calendar software.
Times and dates are parsed semi-intelligently. I didn't write the code that does that, so I don't know precisely what it does. The following kind of things seem to work: