The Transportation Security Administration has spent years pressing the message “If you see something, say something.” But the case before the Supreme Court on Monday was about an airline employee who may have said way too much.

Air Wisconsin is appealing a defamation award of $1.5 million to former pilot William L. Hoeper. He sued after a supervisor with the airline called the TSA in 2004 to warn that Hoeper, about to board a flight as a passenger, was unstable and possibly armed.

The TSA pulled Hoeper from his flight to investigate, and it found that he was unarmed and posed no threat. Colorado courts found the Air Wisconsin supervisor’s warnings so overstated as to be made with a reckless disregard for whether they were true.

But while the justices seemed sympathetic to Hoeper, they were also worried about making it more difficult for airline workers to report suspicious behavior without opening themselves up to lawsuits.

Justice Stephen G. Breyer said he was concerned that workers would be too worried about choosing the right words to report suspicious behavior.

“Why isn’t the best thing to say is, look, there is leeway here, considerable leeway on the part of the airline or anyone else who’s reporting . . . things to TSA,” Breyer said. “All it means is they are going to search him more thoroughly.”

Congress encouraged such reporting after the Sept. 11, 2001, attacks by passing the Aviation and Transportation Security Act. It gave immunity to an airline employee “who makes a voluntary disclosure of any suspicious transaction relevant to a possible” violation of air safety procedures.

But it doesn’t apply when the employee knows the information to be false or when acting with “reckless disregard to the truth or falsity” of the information.

That exception is patterned after the standard the Supreme Court has set in its First Amendment jurisprudence. As a result, a number of media organizations, including The Washington Post, filed an amicus brief siding with Air Wisconsin and urging the court not to relax that requirement. The Obama administration also backed the airline.

But the justices did not seem ready to make broad changes, even though several questioned sharply whether Air Wisconsin supervisor Patrick Doyle embellished his report about Hoeper.

The incident came at a tense time for Hoeper and his employer. Hoeper had three times failed a test required before he could fly a new aircraft Air Wisconsin was about to begin using, and he had been told that if he failed again he would be fired.

At his test in a facility in Northern Virginia, Hoeper said administrators were sabotaging him. He quit, angrily swore at those conducting the tests and said he was calling a union lawyer.

The tester called Doyle, who booked Hoeper on a flight home from Dulles International Airport to Denver, and arranged for an employee to drive him to the airport.

But after discussing the incident with other Air Wisconsin officials, Doyle called the TSA. He said that Hoeper was an “unstable pilot” who was being terminated and that he was “concerned” about the whereabouts of a gun Hoeper was authorized to carry as a federal flight deck officer.

By then, Hoeper’s flight was taxiing before takeoff. The TSA ordered the flight back to the terminal. TSA officials boarded the flight, removed and questioned Hoeper, and determined that he neither had the firearm nor posed a threat. They offered to put him back on the plane; Hoeper declined to reboard, saying he would wait for the next flight.

A divided Colorado Supreme Court upheld a jury award of nearly $1.5 million for what it determined was Air Wisconsin’s defamation of Hoeper.

The airline’s lawyer, Jonathan F. Cohn, told the court that Doyle’s remarks were not false and were in line with what public safety demands.

“These reports are being made by airline employees such as pilots and flight attendants and baggage handlers and ticket agents who are being told by TSA, they have to report in real time without investigation, without calling their lawyer, without stopping to think on how to refine the perfect script,” he said.

Justice Sonia Sotomayor suggested that Doyle did exaggerate his concerns.

“What’s so difficult about simply saying he’s angry?” asked Sotomayor. “Why choose the word ‘mentally unstable’? Isn’t it with an intent to connote something more than the facts?”

Cohn said even a lower-key characterization of Hoeper’s state of mind would still have warranted the TSA to investigate.

Justice Samuel A. Alito Jr. wondered whether it made a difference that the person in question was a pilot.

“My impression of pilots is that they are supposed to remain perfectly calm even when terrible things happen . . . you know, all engines are on fire and one of the wings has fallen off, but, you know, you don’t start ranting and screaming,” Alito said. “And so someone described him as acting in a manner that was more unprofessional than they had ever seen.”

An attorney for Hoeper, Kevin Russell, said his client thought he had been treated unfairly.

Russell said that the federal law granting immunity acknowledged boundaries and that Doyle crossed them.

“Congress didn’t think that the way to promote airline security here is simply to give carte blanche immunity to anybody who reports anything about suspicious activity,” Russell said. “Instead, they recognized that there’s a balance and that people who make bad-faith reports that are materially untrue ought not to be immune” from being sued.

The case is Air Wisconsin Airlines v. Hoeper.