http://www.dailytexanonline.com/worl...o-us-1.1879668
Nine employees of American Airlines have been charged with participating in a smuggling ring that shipped cocaine from Puerto Rico’s main airport aboard flights to the U.S. mainland, officials said Tuesday.
The story goes on to say that this was ongoing over the last decade. In this case just drugs but what would have happened if someone had placed a weapon in one of these shipments?
The OP mentions FedEx cargo but I'm not sure they understand that cargo is also shipped on most passenger flights also. There is a substantial risk because TSA does not conduct 100% screening of these shipments.
Even after that travelers baggage is a threat because it is not held in a secure manner after screening. Airport workers, including TSA, are not screened 100% of the time as they enter the secure areas of the airports. They all have the ability to introduce contraband and have that material placed on aircraft.
Of all the threats against commercial passenger travel by aircraft DHS and TSA have failed the citizens of the US by not closing these obvious weaknesses.
The unanswered question is why?