Contrail does not collect data. It has no account, no analytics, no ads, and no server.
Contrail records your range sessions (video, sound, and the phone's motion, location and compass heading) and keeps them in the app on your iPhone to find and trace your shots. Full session recordings are kept out of iCloud Backup; the shots you keep are small and are included in your iPhone's backup like other app data. Contrail shares nothing with anyone. Delete shots in the app, or delete the app to remove everything.
You can turn any of these off in iOS Settings.
The free trial and the unlock are handled by Apple through the App Store. Contrail never sees your payment details.