Blowing up a plane from the inside is far more difficult and less effective than just setting off a bomb in the security queue. Terrorism isn't rocket science, even dumb as dirt religious fanatics can carry it off successfully.
I work in the physical security field (access control, cameras, alarms, etc.), and carry a multi-tool with a two inch knife blade and screwdrivers in my bag, which I almost always forget to remove before I get to the airport. In five years they've never been noticed. Not once. Know what they've taken repeatedly? My two ounce bottle of Cholula hot sauce. They've told me, "It could be used as a weapon, you could put it in someone's eyes."
Go take your dog for a walk. If you can't think of half a dozen non-suicide attacks on targets within ten kilometers of your house by the time you get home you have no imagination.