You must have the iPad WiFi+Cellular (or iPhone 4 or later) to get a location fix in flight. The WiFi-only iPad model has no internal GPS receiver, therefore you will need to attach an external GPS antenna (Bad Elf, etc).
If you are having problems finding a GPS signal try moving the ipad/iphone to different locations. The GPS antenna on an ipad is located on the top of the device. The GPS antenna on an iphone is the top and sides of it's case. Metal and wiring through the top of the aircraft fuselage can interfere with the GPS signal. The window seat is usually the best location for a GPS signal. In most cases the ipad has a larger GPS antenna, therefore it is able to acquire the signal faster. Holding the top of the ipad against the window will help acquire the GPS signal faster. For the iphone, use either the top or side of the device.
For pilots, the heated front windows in the cockpit may interfere with the GPS signal. Move the device to a side window which is unheated. The GPS antenna is located on the top of the device.
Separate Download: For best results using the separate more detailed download, please use a fast internet connection and download the whole file at once. If you didn't download it all at once and received a download error the app may have issues displaying satellite imagery. If this rare event happens you will need to delete the app and re-download. If you interrupt or stop the download and then re-start the download the progress percentage will not display an accurate percentage. Example: say you downloaded 25% and the connection was stopped or interrupted. When you start the download again it will start at 0% but will be completed at 75% since you already downloaded 25%.