What communication method is represented by SMS in the context of travel services?

The correct answer is Short Message Service, commonly referred to as SMS. In the context of travel services, SMS is utilized for sending brief and efficient text messages to customers regarding various updates, such as flight confirmations, changes in schedules, or important notifications about their journey.

Using SMS allows travel companies like Ryanair to communicate directly with passengers on their mobile devices in real-time, which enhances the customer experience by providing timely and relevant information. This method is favored because it generally has a high open rate, ensuring that the messages are seen by the passengers quickly. Other communication methods, such as social media or standard messaging services, do not have the same immediacy or direct approach that SMS offers in the travel context. Additionally, while service management systems are essential for internal operations, they do not pertain to direct customer communication in the same way that SMS does.