An innovation of Google Flights is that it allows open-ended searches based on criteria other than destination; for example, a user may search for flights within a range of times and a budget and be offered various destination choices. Alternatively, a user can select a destination, and Google Flights will calculate every price for each day of the next 12 months, visualised in a graph or table. This allows users to easily spot the cheapest date to fly to the destination.
The service was immediately compared to competitors such as Expedia, Orbitz, Kayak.com, and Bing. Competitor Kayak.com issued a statement that their service was superior to Google's and that they would be competitive.
There was no immediate change in the price of stocks for Priceline, Expedia, or Travelzoo in response to the opening of Google Flights.
Shortly after the site launched, Expedia testified to the Senate Judiciary Antitrust Subcommittee that Google failed to keep a promise to rank Google Flight listings below the listings of competitors in a Google search.