The Transportation Security Administration (TSA) has kicked off Prohibited Items Week in hopes of alerting more travelers to what they can and can’t bring with them on an airplane to prevent avoidable headaches at security checkpoints.

On Monday, the agency highlighted one of the most common prohibited items travelers bring or often forget in their carry-on, firearms, which must be unloaded and stored in a locked hard-sided container as checked baggage when being transported. Gun owners must also declare the weapon to the airline when checking in.

“It’s always amazing to me when I see the things people try to sneak or how often people forget they have something. Guns are a great example,” TSA Arizona spokesperson Patricia Mancha told FOX 10 Phoenix.

While TSA has reported a dramatic drop in passenger numbers since the COVID-19 pandemic began in March, officers are still seizing firearms at a higher rate than in previous years.

TSA agents found 4,432 firearms at security checkpoints across the country last year. What’s more, a vast majority, 87 percent, were discovered loaded.

“We have seen an uptick of people bringing guns to airports all over the country although we have seen a reduction in travelers,” added Mancha, who also noted that “people are getting a little creative” when it comes to concealing knives.

You can follow along all week long via the TSA Twitter account to learn more about what items are prohibited in addition to mind-boggling stats and some of the craziest things agents have uncovered.

As always, travelers are encouraged to download the MyTSA app or visit TSA.gov to see what items they can and cannot bring with them when flying.