There was a problem like this with an update from a month or two ago. Most people were able to fix it by doing a "Clear Data" on the app. It varies a little depending on your version of Android, but go to Settings/Apps, find the FlyDelta App, hit Storage, and then hit the Clear Data button. This will remove all of the locally stored info and require you to log back in to the app, but I bet it clears up your problem.