Six months after its initial beta launch, Google Flight Search has added dozens of global airlines and international flights to more than 500 airports.
Apart from the addition of dozens of new airlines to Google Flight Search, the launch of international flight search does not involve any new tech or global distribution system partnerships, by all accounts.
The only launch caveat, in what is still a product accessible to US users only, is that the international flights, including roundtrips, must have the initial leg originating from the US to show up.
For example, you see Los Angeles to Sydney roundtrips from Air Pacific, United, Virgin Australia, Delta, Qantas and American and United via San Francisco as long as they originate in the US.
Thus, you won't see Sydney-Los Angeles roundtrips for now.
Google revealed some of the changes in its Inside Search blog and ITA Software blog today.
"A quick click over each city on the map will show the different options available to you almost instantly -- and click the chart next to the dates to show alternative dates so you can make the best choice for your trip," writes Eric Zimmerman, Google product manager, in the blog post.
And, in another tweak, which wasn't discussed in the blog post, booking links from Orbitz, which became ITA Software's first customer in 2001, now appear in some North American search results, breaking the airline-only hold on those precious links.
An Orbitz spokesperson says of the program: "We are always exploring new channel and promotional opportunities and looking at how we might collaborate with Google Flight is among those options."
The deep links to Orbitz, as with airline booking links, are advertisements. For example, here are Orbitz and Alaska Airlines ads on a New York to Vancouver, Canada, search.
The Orbitz ad program in Google Flight Search is a pilot program and Google has the intention of bringing in additional online travel agencies as advertisers with booking links in core search results.
Thus, the business model and Google's issues with some airlines are coming into clear focus.
A Google spokesperson says of the pilot advertising program:

As of today, on certain itineraries, we'll show links to Orbitz as part of the Ads under the “Book” button. Those links will take the user directly to a landing page on Orbitz where they can complete the booking. The Orbitz ad may appear alone or alongside a carrier link depending on whether or not a carrier has enabled deep links with us.
You will see them initially on some U.S.-North American routes, but we're aiming to put OTA links on as many routes as possible to provide users with a comprehensive view of their booking options.
But, even if the online travel agency component of Google Flight Search expands, you likely won't be seeing OTA ads alongside or below some airline's advertisements. The Google spokesperson adds:

As we've said since launch, we absolutely want to include booking links for online travel agencies in Flight Search in addition to the links we show to airline sites. Many of the airlines with which we currently have booking links have not allowed us to include booking links on their flights to other travel sites.
Some airlines, such as American Airlines and Delta Airlines, refuse to participate in flight metasearch unless booking links to their sites appear alone without OTAs in the mix.
Thus, the comprehensiveness of Google Flight Search when it comes to enabling bookings on airline and online travel agency sites will be challenged based on Google's insistence on sticking with an advertising model. Google doesn't show booking links unless airlines are advertising and Google Flight Search isn't displaying advertisements from Orbitz unless the particular airline gives its OK.
Google, which obviously seeks comprehensive and advertising revenue, is urging its airline partners to play nice with the OTAs.
"Like any other travel-search site, we need to respect each airline’s distribution decisions," the Google spokesperson says. "However, we strongly encourage our airline partners to allow OTAs to participate in initiatives like Flight Search."
When an airline or Orbitz is running booking link advertisements in Google Flight Search, the Book button is red.
When airlines have not given Google permission to deep link to their sites and are not participating advertisers, then the Book button is grayed out. In the following screenshot, showing a United Airlines and ANA roundtrip New York to Tokyo, you can see that Google Flight Search has no booking option as the Book button is disabled.
So why has Google chosen to include international flights, but only those originating from the US?
Why produce a limited product when international flights have been so greatly anticipated?
And, what about the inevitable blasts from critics that Google Flight Search is a failure because so many international flights are still missing?
Google's thinking is that it wants to develop Google Flight Search incrementally and in a way that is beneficial to travelers.
And, you might consider what Google and ITA have done so far with GFS as an early look at an evolving product.
After all, what in tech doesn't evolve?
So today's rollout of flights is relatively comprehensive regarding routes from the US to popular destinations around the world.
Along similar lines, ITA Software's QPX service has featured international flight search since at least 2003.
But, Google didn't want to introduce routes from global destinations when it doesn't yet have access to the full roster of options.
For example, while Google Flight Search certainly could have introduced flights from Paris, it didn't want to do so if it only included a subset of flights from and to certain airports there.
There can be no doubt that Google is working on globalizing access to Google Flights Search and a producing a fully international product, which might require new tech partners.
Regarding the dozens of new airlines included in flight search results, it is believed that Google Flight Search doesn't necessarily have partnerships or commercial relationships with many, but is working on establishing them.