Case Study 7: Google-ITA

Topper, Michael D., Stanley Watt, and Jingming "Marshall" Yan. (2014). "Google-ITA: Creating a New Flight Search Competitor (2011)" in John Kwoka and Lawrence White (eds), Antitrust Revolution: Economics, Competition, and Policy, 6rd edition, Oxford University Press.

What were the competitive alternative P&S systems available to Google's competitor in flight search services?

(The answer is in the link I provided above I have a answer just want another answer from an expert I WILL LEAVE GREAT FEEDBACK ONLY IF THE ANSWER IS CORRECT YOU HAVE MY WORD!)