A travel booking engine manages complex multi-destination itineraries through various features and functionalities:

. Itinerary Management Tools: The engine provides tools to create, modify, and manage multi-destination itineraries. Users can add multiple destinations, arrange travel segments, and view the complete itinerary in a structured format.

. Optimizing Routes: The system optimizes travel routes to ensure efficient and cost-effective travel plans. It calculates the best possible routes based on factors such as travel time, cost, and availability, helping users plan their journeys more effectively.

. Offering Flexible Booking Options: The engine supports flexible booking options that allow users to adjust travel dates, modify destinations, and customize their itineraries according to their preferences.

Overall, itinerary management tools, route optimization, and flexible booking options enable travel booking engines to handle complex multi-destination itineraries efficiently, providing a comprehensive and user-friendly experience.