Tutorial of configuration export bookings from Booking Calendar into other services, like Google Calendar or Airbnb, Booking.com, HomeAway, TripAdvisor, VRBO, FlipKey and any other calendar that uses .ics format.
Please read more about this feature here.
Please note. Booking Calendar is generate .ics feed with bookings in real time. But how often some service (like airbnb, or booking.com ) access this .ics feed to import the bookings from Booking Calendar into own system, does not depend from Booking Calendar. So in other words, Booking Calendar does not force to generate import process by third party service, when some booking is created. You need to check with support of this service (like airbnb or booking.com), about how often they can access .ics feed tor making import.