Major airline
Although this airline I'm talking about doesn't use AirApps because they have their own online app I though I'd mention what a friend told me that he experienced when he interviewed. I can't mention the airline name, but it's a major.
Before the interview, they gave him a printout of his application to review and sign. At the back, was a several page listing of each time (listing date and time) he had logged in and what he had changed (ie: jet pic changed from 1021 to 1142, etc).
In this day of unlimited storage and the ability to search easily, if you've done something online - posted a picture, written a entry on a website, it's accessible by someone forever. I think the same thing exists with application - I imagine if he reapplies to this airline, they'll compare his new app with the old one and see what's changed.