The latest info on AirAsia X mobile apps
The iOS apps from AirAsia X will work with all of your Apple devices, from iPad to iPhone
For AirAsia X BIG members, you'll be able to manage your account from the app, though using their website will no doubt provide more functionality
AirAsia X has an Android app that works with most Android tablets, phones, and some Android Wear devices. Perhaps standard practice these days, the Android app offers the same functionality as the iOS app from AirAsia X.
If you're just looking for their mobile site, you can head on over to http://www.airasia.com on your mobile device.