Expedia has just announced that it has acquired developer Mobiata, the creator of popular mobile travel application FlightTrack. Terms of the deal were not disclosed.

Mobiata creates a number of travel mobile applications including FlightTrack, TripDeck, HotelPal FlightBoard and FareCompare. FlightTrack is the developer&'s most popular app and lets you check flight status, access information about delays or reschedules, locate your flight&'s gates, and see real-time tracking maps of flights. FlightTrack is currently a best selling iPhone travel app in the App Store. A Pro Version of FlightTrack is also integrated into TripIt Pro. We&'re not sure if that relationship will continue post-acquisition.

According to the release, the acquisition represents Expedia&'s &''most significant investment to date in addressing the mobile travel market.&'' Expedia is currently seeing 4 percent of its traffic coming from mobile browsers or app, and hopes to grow this number through the acquisition.

This week also brought the news that travel search aggregator Kayak.com is filing for a $50 million IPO. And the online travel industry is in a state of flux awaiting whether Google&'s $700 million acquisition of ITA Software (which powers flight listings for both Kayak and Expedia) will be given the green-light by the Justice Department.