Earlier today we released version 6.2 which includes support for our new data sync capability. Some customers are experiencing an app close after updating to 6.2, which is a result of a data migration process when run against large numbers of recent routes and plates.
We jumped on a fix as soon as the issue was detected. A fix for customers experiencing this issue is in version 6.2.1, which is submitted to App Store and pending review. As a workaround, customers can delete and reinstall the app if they need to bypass the issue.
Read more here: ForeFlight Mobile 6.2.1 Submitted to App Store