The Transportation Security Administration thought it had settled a dispute over peanut butter some time ago: unless it is 3.4 fluid ounces or less, it has to be checked.
However, the question of what the T.S.A. considers a liquid continues to confuse passengers. It bubbled up again last week when a writer and podcaster tried to board a flight out of Pittsburgh with a jar of Jif natural peanut butter.
Patrick Neve, who said he was on the way to a speaking engagement, wrote about surrendering his peanut butter in a tweet that had received 10.4 million views by Monday, according to Twitter.
“I tried to take peanut butter through airport security,” he wrote. “T.S.A.: ‘Sorry, no liquids, gels, or aerosols.’ Me: ‘I want you to tell me which of those things you think peanut butter is,’” he continued, lightheartedly summarizing his conundrum.
He asked; T.S.A. answered.
The administration, which takes a decidedly lighter tone online than its officers do at airport security lines — with a bio promising “travel tips and dad joke hits” — responded with a reiteration of its peanut-butter rule, and a bad pun.
“You may not be nuts about it,” the administration’s social media team posted on Instagram, “but T.S.A. considers your PB a liquid. In carry-on, it needs to be 3.4 oz. or less.”
Mr. Neve’s experience with T.S.A., earlier reported by The Washington Post, inspired travelers to share their own tales of loss to the exacting standards of a T.S.A. security line, many of them with more than a hint of snark.
“So apparently my peanut butter wasn’t allowed past security but the 22-gauge IV insertion kits that were somehow at the bottom of my carry-on bag passed with flying colors,” Blimi Marcus, a registered nurse, wrote on Twitter
The T.S.A.’s Instagram post reminder included the textbook definition of a liquid: something that “has no definite shape and take a shape dictated by its container.”
By that definition, several people wrote in the post’s comments, neither cats nor cranberry sauce should be allowed onboard.
Peanut butter is considered to be “spreadable,” so it falls under the rule for liquids, gels and aerosols, a T.S.A. spokesman, R. Carter Langston, said in an email.
“As we frequently seek to remind travelers: If you can spill it, spray it, spread it, pump it or pour it, then it’s subject to the 3.4-ounce limitation,” he said.
Unlike with firearms — there were a record 6,301 guns intercepted by T.S.A. in 2022 — the administration does not track the quantity of food or other goods it asks passengers to either check or surrender.
Aside from items deemed useful as props in media demonstrations at regional airports, the majority of what travelers hand over gets thrown away, Mr. Langston said.
Aware that stressed-out travelers are often frustrated with the T.S.A. rules for the contents of their carry-on luggage, Janis Burl, a social media branch manager at the agency, decided to try a different tack online.
Under her stewardship, the administration’s Instagram account, with its playful tone and direct messages to confused passengers, has attracted some 1.2 million followers.
The account’s mission is to speak to “the common traveler,” Mr. Langston said.
“Sometimes it takes a little more cheek to resonate with people, particularly over social media,” he said.
All joking aside, T.S.A. officials say that the risks of explosives onboard have not abated since 2006, when the limits on liquids first came into force in response to the Sept. 11 attacks and several other bombing attempts on aviation.
The rules came about as part of the Aviation and Transportation Security Act signed into law by former President George W. Bush in November 2001, mandating that federal officials conduct enhanced screening at airport checkpoints.
The T.S.A. set up explosive detection systems, the technology for which has advanced over the years, leading some critics to wonder whether peanut butter, perfume and water bottles should remain under such scrutiny.
The 3.4-ounce limit is a standard set by the International Civil Aviation Organization, Mr. Langston said, calling it “still very much a necessary risk-based rule.”