Background operation
Enable background and startup behavior in Settings. Closing the main window can leave one AeroMailer icon in the system tray so active campaigns continue. Reopening AeroMailer should reuse the existing app process rather than create duplicate tray icons.
Sending indicator
When a campaign is actively sending, the tray icon displays its sending state.
Notifications
When enabled, desktop notifications announce campaign start and campaign completion. Operating-system notification permissions must also allow AeroMailer notifications.