dumb.py

class BookingManager(models.Manager):

    @property
    def departures_today(self):
        return Booking.objects.filter(start__gte=self._this_morning, start__lt=self._tomorrow_morning)

    @property
    def arrivals_today(self):
        return Booking.objects.filter(end__gte=self._this_morning, end__lt=self._tomorrow_morning)