When Google bought ITA, it was clear that it could create its own flight search tools to compete with the likes of Kayak or Priceline.

FORBES: Guess Who Spends $1 Billion a Year on Search Terms and Mightn't Like Google's Frommer Deal?

Critics of a Google-ITA combination say it would give Google a further leg up in the search industry, which it dominates.

WSJ: ITA Becomes Hot Ticket

Moreover, it could also stop licensing ITA at favorable terms.

FORBES: Guess Who Spends $1 Billion a Year on Search Terms and Mightn't Like Google's Frommer Deal?