Remember in Gateways, Jack wants [SPOILER]to be able to fight should his plane be hijacked. To fool the security portal, he tapes a Plexiglas knife to his arm.
[/SPOILER]
It might not be possible in the future:
[SPOILER]
"a machine the company makes in St. Petersburg, Florida -- one that creates explicit images of traveler's bodies to find weapons under their clothes."
http://hsdailywire.com/single.php?id=6774
If Jack must travel again, he'll have to chose very carefully his airports...[/SPOILER]
As an aside, I wonder how long it will take before the images find their way on internet?