Shopping malls are likely the new target... all the DHS gumshoes are looking at airports while shopping malls are large inviting targets that have little security. The Somali al Shabob terrorists hit a western style shopping mall in Kenya a year ago...I think that was a dress rehearsal for a similar attack in the US. Minneapolis has the largest shopping mall in the country, Mall of America, and tens of thousands of Somalis some of whom have already been recruited and trained by al Shabob in Somalia. Connect the dots
If you think shopping malls are vulnerable, go look at your local natural gas pumping station, or local electric substation. Think winter. Think no heat, no electricity. Think frozen.