A more pressing question is what would happen to QPX, ITA's flight search system. Google's policy of making acquired companies rewrite their software according to Google's standards would, if applied, mean rewriting QPX in C++, Java, or Python. Given how often QPX has been cited as a system that leverages the power of Common Lisp to do complex things, that would be an interesting thing to follow. I bet Google wouldn't do that, though. For an acquisition of this size (the article says $1B), the rules are probably different. (Did they rewrite Youtube?) I must say it would be neat to see Google break their no-Lisp policy.
(As a side note, it's true that if you don't care that much about continuing to evolve a complex Lisp system, it's often possible to rewrite it in a less powerful language; you just end up with a larger and less changeable codebase.)