The Department of Homeland Security has spent billions since 9/11 trying to keep dangerous people and dangerous explosives off airplanes, and treating us all air travelers like potential terrorists in the process. But according to a former security adviser to a leading airline, the terrorists have changed the game — and the government hasn’t yet caught on.

According to Ben Brandt, a former adviser to Delta, the airlines and the feds should be less concerned with what gels your aunt puts in her carry-on, and more concerned about lax screening for terrorist sympathizers among the airlines’ own w...

Space, as Douglas Adams once so aptly wrote, is big.

To try imagining how big, place a penny down in front of you. If our sun were the size of that penny, the nearest star, Alpha Centauri, would be 350 miles away. Depending on where you live, that’s very likely in the next state (or possibly country) over.

Attempting to imagine distances larger than this quickly becomes troublesome. At this scale, the Milky Way galaxy would be 7.5 million miles across, or more than 30 times the distance between the Earth and the moon. As you can see, these are rather inhuman dimensions that are almost...