News this week that Microsoft's fully functioning Bing Travel will not be hitting Europe in 2009 means that another site from the US with air price data prediction tools at its heart, FareCompare, might make it first.
Bing says the complexity of gathering historic data about fares over any given period is time consuming and has affected its ability to launch the Farecast system overseas.
FareCompare faces similar issues on the number crunching front, but has a roadmap which could see it outside of the US sooner than Bing Travel.
FareCompare is aiming to have worldwide coverage of ATPCO data (a body which collects fare data on behalf of the industry) by January 2010, says CEO Rick Seaney.
The company currently has domestic US and Canadian data from October 2004 to the present day and in/outbound for the US and Canada since January 2006.
The influx of worldwide data, Seaney says, means FareCompare will be pricing "millions of new itineraries" every day.
"Our aspiration is to have worldwide coverage of the most comprehensive database in the world of current and historical airfare pricing data and to bring to market a variety of tools that slices this massive database to the marketplace, via dot-com and social media."
The question for potential European rivals of FareCompare and Bing will be if they can afford to get their hands on - or have a desire to include - similar data sets in order to publish the prediction tools which have made the two US sites popular.