Another warning about IEDs targeting airliners. Another announcement that aviation security will work to address the threat.

We are now hearing that the rise of ISIS has many officials believing that terrorists will once again target commercial flights.

This is a bit confusing, as terrorists never halted trying to destroy airliners. This has been an ongoing battle, dating back to the dawn of commercial air travel.

In 1933, a United Airlines flight bound for Chicago left Cleveland at 6:57pm with four passengers and three crewmembers. A little after 9:00pm, the Boeing 267 exploded over Chesterton, Indiana, killing everyone on board.

Given the nature of the crash, the size of the debris field, and eyewitness statements, conclusions for the reason of the explosion immediately focused on a bomb.

The U.S. Department of Commerce, who investigated the crash, determined the aircraft was destroyed by an explosive device; possibly a container of nitroglycerin attached to a timing device. No one was ever charged.

In the current day, where the specter of international terrorism and criminality continues to play a key role in shaping the geopolitical and economic climate, we would be wise to remember that attacks against civil aviation are as old as commercial air travel itself.