What can you bring in your luggage? Changes to US flying rules surprise thousands of passengers.

A new regulation is now in effect at several airports across the country. The measure represents a significant change from the security policies in place.

Did you know that the rules for flights in the United States are changing from now on? Yes, for weeks now, U.S. authorities have quietly begun implementing a change that modifies what passengers can carry in their carry-on luggage. A truly positive measure for most travelers.

And while we can say it hasn't been announced with much fanfare, the impact is already being felt at airports like JFK, Atlanta, and LAX—some of the largest in the country. Security checkpoints there now incorporate technology that allows for the relaxation of restrictions that have been in place for more than 20 years.

You can now fly with items or products that were previously prohibited. Computed tomography (CT) scanners, capable of generating highly accurate three-dimensional images, are allowing the TSA to relax its rules on liquids. Some passengers have been able to board domestic flights carrying items that until recently were prohibited if they exceeded 100 milliliters.

What liquids can be carried without limit?

Among the products now permitted, without quantity limits, are those on this list, although they are not the only ones:

• Liquid, gel, or aerosol medications, prescription or over-the-counter
• Breast milk and baby formula
• Children's food and drink
• Ice or gel for medical use
• Liquid-filled teethers
• Fresh eggs
• Sealed duty-free items
• Biologic specialties
• Live fish in water

Wet batteries and other items that, until recently, caused delays at security checkpoints are now allowed. However, this is just the beginning. The TSA has indicated that these changes will be phased in. Although they are already in place at several airports across the country, not all of them yet apply the new regulations. Therefore, it is recommended to check local regulations before traveling. For international flights, the restrictions remain in place.

What about shampoo, sunscreen, and perfume?

For now, these items remain subject to the old 3.4-ounce (100 ml) limit, but the TSA itself has confirmed that it is considering removing them from the restricted list once the new scanners are fully deployed.

If you have questions, we have the free myTSA tool to check what you can bring on board. You can also ask @AskTSA on Twitter or Facebook Messenger.

Faster at the airport

According to the TSA, the new scanners not only improve security but also reduce the number of manual checks. This speeds up lines and avoids frequent inconveniences for those traveling with children, medications, or special needs.

Christopher Murgia, director of federal security in Maryland, advised passengers to "be familiar with the contents of their carry-on bag and avoid last-minute packing" to avoid missing their flight due to carelessness.

Goodbye to small bottles

Liquid restrictions arose after a foiled plot in 2006 to use liquid explosives on airplanes. Since then, millions of travelers have had to adapt to the 100 ml rule. Now, with the help of technology, the rules are beginning to be relaxed, although the change will be gradual. This could mark the end of the small-bottle requirement.

Some travelers are celebrating the news. Others are still wary, perhaps because they feel less secure. But the truth is that, after years of rigidity, flying within the United States could finally become a little less stressful. But for now, it will only be within the United States.

Of course, travel from the United States to Cuba is a different story. The General Customs Office of the Republic has very strict regulations, and a few weeks ago it was revealed that they would be closely scrutinizing everything arriving from the United States.