Not all airlines are on Google Flights. One major exception in the US is Southwest Airlines, which does not list its fares on Google Flights. Several large Asian carriers are also absent from the results, including Air China, China Eastern, Thai Airways, and Philippine Airlines.

While Google Flights covers the vast majority of global carriers, some notable airlines limit their participation or are excluded entirely. The most famous example is Southwest Airlines, which typically requires users to book directly on their website, though they have recently begun showing some data on the platform. Other exclusions often include ultra-low-cost carriers (ULCCs) in specific regions or smaller regional airlines in Asia and Africa that do not use major Global Distribution Systems. Additionally, some airlines may show flight times on Google but won't provide a direct booking link or price. For the most comprehensive search, it is often recommended to cross-reference Google Flights with Skyscanner or Momondo.