The Google Flights API, which was deprecated on April 10, 2018, enabled developers to access and integrate flight search and pricing data into their applications by leveraging Google Flights' comprehensive capabilities. Despite its discontinuation, alternatives like the Skyscanner Flights API are recommended for similar functionalities. Google Flights, originating from Google's acquisition of ITA Software and its QPX API, provided an intuitive interface for users to search flights by price across multiple airlines without discrimination. The API offered endpoints for searching single trips or multiple trips, and while the first 50 queries per day were free, subsequent queries incurred a fee. Developers were encouraged to incorporate the API into projects, such as creating travel apps or integrating with other services like text messaging for flight notifications, highlighting its versatility in application development.