code: public FlightInfoBuilder<T> setFlightSchedule(Calendar departureTime,
  			Calendar arrivalTime) {
  		FlightSchedule flightSchedule = new FlightSchedule(departureTime,
  				arrivalTime);
  		this.flightInfo.setFlightSchedule(flightSchedule);
  		return this;
  	}
docs: Sets the {@link FlightSchedule} object for the current {@link FlightInfo}
  object. This field is mandatory for this object and can't be null.
  
  @param departureTime
  the departure time. It can't be null.
  @param arrivalTime
  the arrival time. It can't be null.
  @return this builder.