At the start of the year, Hopper unveiled an iOS app with data-driven flight predictions. This product, which featured airfare forecasts and ticket price tracking, has gained traction with users.
This week it released an Android version of the Hopper cheap flights app. In the company's words, the app analyzes billions of flight prices a day to provide advice on when to fly and buy, as well as help a person track flights. The company says:

"In 95% of cases, following Hopper's price prediction will get you a cheaper flight or at least the same price as found in your initial search."
This new one-minute video shows the product in action:
For its iOS app, Hopper also adds QuickTap Booking, which offers instant booking within the mobile app interface. This feature will be added to Android soon.
On the backend, Hopper's data team has moved to using Spark, instead of Hadoop. Says the company:

"The fact that Spark has both batch-oriented and stream-oriented processing baked in was very compelling for us since our existing infrastructure relied on different technologies to serve these workloads.
The deciding factor for using Spark was that our data science team can also use Spark during the R&D phase which dramatically reduces the time required to move their new algorithms over to actual usable features for our users."
Q&A on Hopper's cheap flights search model
Disclosure: Frederic Lalonde is chairman, co-founder and an investor in Tnooz.