Flying? Check Latest Carry-On Rules

At first, the rules on what's permitted in carry-on bags were not very detailed. Since then, the Transportation Security Administration (TSA) has refined those rules several times.

"Travelers may now carry through security checkpoints travel-sized toiletries (3 ounces or less) that fit comfortably in one quart-size, clear plastic, zip-top bag," states the TSA's web site.

At the security checkpoint, "travelers will be asked to remove the zip-top bag of liquids and place it in a bin or on the conveyor belt," the TSA notes.

"In addition, larger amounts of prescription liquid medications, baby formula, and diabetic glucose treatments must be declared at the checkpoint for additional screening," states the TSA.

But don't try to go through an airport security checkpoint with a large cup of coffee or a big bottle of water. Those items aren't allowed through security but can be bought at airport shops near your departure gate.

"After clearing security, travelers can now bring beverages and other items purchased in the secure boarding area on-board aircraft," states the TSA.

According to the TSA, items currently permitted in carry-on bags include:

• Baby formula and breast milk if a baby or small child is traveling
• AsthmaAsthma inhalers
• All prescription and over-the-counter medications (liquids, gels, and aerosols) including KY jelly, eye drops, and saline solution for medical purposes
• Liquids including water, juice, or liquid nutritionnutrition or gels for passengers with a disability or medical condition
• Life-support and life-sustaining liquids such as bone marrow, blood products, and transplant organs
• Items used to augment the body for medical or cosmetic reasons such as mastectomy products, prosthetic breasts, bras or shells containing gels, saline solution, or other liquids
• Gels or frozen liquids needed to cool disability or medically related items used by persons with disabilities or medical conditions.

Passengers can carry as much of those items as they want in their checked baggage. But if the medically necessary items exceed 3 ounces or are not contained in a one-quart, zip-top plastic bag, passengers must present those items for inspection at the security checkpoint.

"All disability-related equipment, aids, and devices continue to be allowed through security checkpoints once cleared through screening," states the TSA.