Who Benefits from Google Search? The Impact of the Digital Markets Act on the Air Travel Market

This paper examines the impact of Google’s Search Engine Results Page (SERP) redesign on web traffic to airline and flight comparison websites. Google implemented the redesign on March 6, 2024, in response to the Digital Markets Act (DMA). The reform removed the Google Flights module from the main results page and introduced two new sections — “Airline Options” and “Flight Sites”— aimed at reducing self-preferencing and increasing the visibility of third-party services. Using a Synthetic Difference-in-Differences (SDiD) approach and domain-level data for four EU countries, with the United Kingdom and the United States as control markets, we estimate the causal effects of the redesign from November 2023 to December 2024. We find that the reform reallocated organic search traffic toward airline and comparison websites with smaller market shares. On desktop devices, organic traffic to low-cost and network airlines increased by 15 percent and 5.5 percent, respectively, while no significant effects are detected on mobile. Traffic to flight comparison websites increased by 20 percent on desktop and 19 percent on mobile, with gains concentrated among smaller platforms. By contrast, we find no detectable effects for large incumbents such as Skyscanner, Booking.com, and Expedia. Overall, the redesign relaxed visibility constraints for smaller market participants, suggesting that digital market regulation can increase contestability at the margin without necessarily altering the position of large incumbents.