The Transportation Security Administration now permits passengers to board airplanes with large bottles of medically necessary liquids that exceed the agency's 3-ounce limit.
But there's a catch.
The catch is that passengers -- no matter how experienced with TSA security lines and procedures -- must go through specially marked family lanes equipped with scanners able to detect liquid explosives.
"It can delay your screening process if you have those liquids. But, on the other hand, it keeps you from having to put those items into checked baggage, as you had to before," said Dwayne Baird, TSA Salt Lake City spokesman, on Tuesday.
TSA rolled out the new procedure at Salt Lake City International Airport on Thursday - one week ahead of the Thanksgiving holiday, when, according to the Air Transport Association of America, planes are expected to be close to 90 percent full despite a projected 10 percent decrease in passenger numbers.
While 32-ounce bottles of shampoo still aren't allowed aboard flights, large bottles of substances such as cough syrup, insulin, prescription medications and breast milk are, Baird said.
"Anything that will allow passengers to carry more than 3 ounces will be a great benefit," said David Stempler, president of the Air Travelers Association. "They can either bring the liquids or go through the fast lanes. It's their choice."
TSA bills the procedure as an expansion of the "Black Diamond" program it launched nationwide in February. The program allows passengers to choose a security lane that matches their level of familiarity with TSA rules and regulations.
Passengers who know TSA procedures and understand the agency's 3-1-1 liquids policy (bottles 3 ounces or less by volume, inside one zip-top bag, in one screening bin) can go through expert lanes marked with a black diamond.
TSA representatives guide travelers marginally familiar with the agency's routines into blue square lines. Families and beginners who need extra time can choose green circle lines.
"We do have customer representatives" to help travelers, Baird said. "We may not have them at slower times of the day, but when that queue fills up we do have customer service representatives who are out front leading them into the proper lane of travel."
Baird said the black diamond program has eased stress and sped up security checks at Terminal 1 in Salt Lake City. The program isn't used in Terminal 2, where passengers board Delta Air Lines flights, because it hasn't been necessary, he said.
"We used to track our wait times in the lines [but they have] diminished so drastically that we've even dropped calculating wait times," said Baird.