Any alert that we have sent out email or text messages for will show up on the history page. Click View History on the Flight Alerts console to see history. Alerts are grouped in months, so if you are looking for a much older alert first select the month of the flight departure. The month can be chosen by dragging the graph selector to the proper month, or by clicking on the month filter.
In the stats section of the screen, there is a Flights Monitored box that will show you have many alerts were set up for that month.