1) There isn't a direct visual relationship between the "depart" / "return" fields and the date picker (i.e. I didn't see a standard dropdown or calendar icon or way to pick a date)
2) I didn't realize that the date picker widget is one calendar, spanning two months. I thought it was two calendars: one for depart, one for return.
Wondering: Am I the only one? Did they actually test this? Would a "traditional" design with two fields, each with a calendar icon / dropdown perform better? OR, maybe two fields and one calendar beside or beneath each?