In the years since 9/11, airplane safety has been a subject of constant conversation. Looking back over the past decade alone, there have been several notable incidents involving commercial flights that still puzzle investigators.

The mysterious crash of EgyptAir Flight 804 on Thursday morning is just the latest such incident. Check out the timeline below to read about other puzzling crashes, airplane disappearances, attacks and hijackings since 2006.

Clint Davis is a reporter for the Scripps National Desk. Follow him on Twitter @MrClintDavis.