One of these snow globes doesn't belong onboard. The one on the left, which is about the size of a tennis ball, is permitted in your carry-on luggage. The one on the right is not.
The airline industry predicts some 42 million of us will be flying this holiday season, and that this weekend before Christmas will be one of the busiest periods.
For tips on how to get through what's expected to be some long security lines, we turn to the Transportation Security Administration's Lisa Farbstein. She says there's a useful guide on the TSA's homepage that allows you to type in an item to see if it's allowed in your carry-on, as well as a mobile app.
She also offers some basic advice, saying if an item is over 3.4 ounces and "you can spill it, spread it, smear it, squeeze it, spray it, pump it, or pour it," then you should place it in your checked baggage.
But, there is some good news this holiday season: You can now carry on small snow globes, as long as they are put in those plastic bags along with your other small bottles of liquids.
Snow globes smaller than a tennis ball are now OK to bring onboard a plane, and, by the way, so are pies and fruitcakes. But not jars of jam or jelly or cranberry sauce over 3.4 ounces. They must be put in your checked luggage.
Other advice: Wrapped presents aren't such a good idea, because if the TSA officers can't tell what's in the box, they'll want to unwrap it. Farbstein suggests using gift bags.
And new this year, if you're traveling with children younger than 12, they don't have to take off their shoes. Neither do you if you're 75 or older.
"We recognize that they're not likely to be terrorists and so we allow them to leave their shoes on. That expedites the screening process," Farbstein says. "Basically, we do know that not everybody is a terrorist. We totally understand that."
But the TSA's critics say they don't really understand that.
"These kinds of rules really don't make any sense today, and we spend literally millions and millions of dollars searching for items now, which are of no harm," says Charlie Leocha, director of the Consumer Travel Alliance.
After the Sept. 11, 2001, attacks, the government ordered airlines to install hardened locked doors to the cockpit. Leocha says that pretty much eliminated the danger from small pocketknives, box cutters and the like. So he says those intrusive searches at airport checkpoints are totally unnecessary.
"You can't break into the cockpits anymore. They get locked up and the pilots are safe, and we have an incredible intelligence operation going on, which now allows the government to screen every passenger for every flight against a terrorist watch list," Leocha tells NPR.
Leocha says the TSA should go back to using standard metal detectors at security checkpoints rather than the full body scanners, which have raised concerns about privacy and safety.
But for now, holiday air travelers have no choice but to prepare themselves.
So remember, you can carry on a snow globe no bigger than a tennis ball, but that gift jar of cherry preserves will have to stay in a checked bag.