A word of warning for those short-tempered souls battling long airport security lines on their way back from their holiday travels: Your fellow passengers are just as stressed and more likely this year to be armed to the teeth.

The federal Transportation Security Administration caught more people in 2014 trying to slip firearms, knives, grenades, and even swords through security screening checkpoints than in any year in the last decade, according to agency statistics.

As of Dec. 25, TSA agents had retrieved 2,164 guns from carry-ons, purses, and coat pockets - a nearly 20 percent increase over last year. In fact, the number of weapons agents have seized has increased every year since 2007.

That steady rise has security officials perplexed. For all the attention and controversy heightened airport security measures have received since Sept. 11, 2001, who still thinks they won't get caught packing heat in their carry-ons?

Last month, at the start of the holiday travel season, the agency launched a media campaign at airports to remind people to check their guns or leave them at home. Those caught trying to slip a weapon through a checkpoint can face fines of up to $11,000 and possible criminal charges.

Not to mention the wrath of everyone else waiting in line: "Every time TSA discovers a firearm in a bag at the checkpoint, it delays the screening process for all travelers," said Ross Feinstein, an agency spokesman.

Travelers at Philadelphia International Airport, where 11 guns have been uncovered this year, hardly rank among the nation's worst offenders. (Here's looking at you, Texas, with your 284 guns seized at TSA checkpoints in Dallas and Houston.)

But don't breathe easy just yet. What local passengers lack in sheer size of their airport arsenals, they more than make up for in ingenuity.

Consider a few of this year's highlights from the TSA Blog, a colorful catalog of the contraband confiscated at checkpoints nationwide:

In October, X-ray scans at Philadelphia International revealed one passenger had packed a knife in a neck pillow - a move rivaled only by the traveler found a month later with a blade hidden in the heel of a shoe.

Another passenger was stopped in May with a hollowed-out textbook hiding 70 pills.

And just last week, Philadelphia airport screeners encountered a man with hidden knives - hidden, that is, inside a pen and a highlighter clipped to his shirt pocket.

That latest discovery appeared in the confidence-instilling blog post titled, "37 Loaded Firearms, Five Inert Grenades, Black Powder Pellets & More," detailing TSA's nationwide Christmas-week haul.

TSA officials say most travelers caught with firearms claim they simply forgot the guns in their bags. That was the explanation NBA Hall of Famer Bill Russell offered when agents in Seattle found a loaded .38-caliber Smith & Wesson pistol in the Boston Celtics great's carry-on last year.

Russell later apologized and still made his flight.

Kathryn Spiropoulos, a 53-year-old school administrator from Ewing, N.J., wasn't so lucky. She found herself in handcuffs after TSA agents in Philadelphia detected an unlicensed and loaded Glock .45-caliber handgun tucked in her purse - next to a credit card-shaped knife.

So much for flying the friendly skies.