You cannot; Apple doesn't allow anyone to access the XML files to make the modifications. I don't know how familiar you are with XML editing (I was not until I fooled around with it in SP), but you open the XML aircraft files, which are in a sub-folder under "Jundroo", edit the values in the file and save the edited files. As t8erh8er states below, there's no way to get into those files in iOS. It's Apple's policy for all their software and Jundroo can't do anything about it.
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You cannot; Apple doesn't allow anyone to access the XML files to make the modifications. I don't know how familiar you are with XML editing (I was not until I fooled around with it in SP), but you open the XML aircraft files, which are in a sub-folder under "Jundroo", edit the values in the file and save the edited files. As t8erh8er states below, there's no way to get into those files in iOS. It's Apple's policy for all their software and Jundroo can't do anything about it.