JACKSONVILLE, Fla. -- Bored on a hot summer day, three Florida youngsters were just sitting around when one sent a text message to another with an adventurous idea.

"Hey do you want to go 2 Tennessee today," the message read.

"Sure," the other responded.

Not even old enough to get a driver's license, they took a taxi to the airport Tuesday, bought tickets with baby-sitting money and -- unbeknownst to their parents, the three (ages 15, 13 and 11) -- boarded a Southwest Airlines flight from Jacksonville to Nashville, according to a TV news account of the incident.

Nobody asked a question. Nobody asked for identification.

Not the taxi driver. Not the ticket counter. Not security officials or flight attendants or other passengers. So when they landed in Nashville with just $40 left and their destination, Dollywood, still hundreds of miles away, they finally called home. The jig was up. "I just wanted to fly," Bridget Brown, 15, told WJXX-TV in Jacksonville. "I had the money."

Now their parents are wondering how the trip was possible.

Southwest Airlines said in a statement that the company's policy on minors is similar to other carriers in that it covers children ages 5-11 traveling alone, and that the 11-year-old in this case was accompanied by two older companions. The Transportation Security Administration does not require anyone under age 18 to show identification, but all bags are still screened.

It is unclear if any of the three should have been allowed to purchase tickets. A Southwest spokesman did not immediately return a message seeking comment on that issue.

Messages left by The Associated Press on Friday at the families' homes were not immediately returned.

In an age of heightened security and terrorism threats, some are concerned that three youngsters could easily board an airline without parental consent.

Richard Bloom, an aviation security expert at Embry-Riddle Aeronautical University in Daytona Beach, Fla., said while this incident amounted to a childhood jaunt, it highlights legitimate safety implications.

"The moral of the story is, at least in other parts of the world, young people are engaged in weapons, planting bombs, testing security," he said. "The point is terrorist groups, insurgent groups, other kinds of transnational groups, what have you, they read the papers, they watch TV, they look at the security lapses. And they take that information as they develop their own terrorist operations and anti-government operations."

Sari Koshetz, a TSA spokeswoman, dismissed the idea that children would have an easier time of getting weapons onto a plane. "Our mission is to make sure that all passengers, regardless of age, are screened thoroughly to make sure they don't pose a threat to the aviation system," she said.

The three youths certainly had no problem hopping a flight.

Brown, with the $700 she had saved, took her 11-year-old brother, Kodie, and 13-year-old friend Bobby Nolan III to the airport in the early afternoon. She said she purchased the three tickets at the Southwest Airlines counter without any problems from the clerk.

"He said OK and told us how much it would be and then we paid him," Brown said. "Then he put the flight things on our bags, and then he said, 'You better run because you might miss your flight.' "

No issues at security, either.

"We just took our stuff out of our pockets, took our shoes off and walked through it," Nolan told the TV station.

The three arrived in Nashville and, realizing their plan was flawed, finally 'fessed up.

Their parents came home from work and thought the kids were out playing. They had left messages on the children's cell phones that went unreturned. When their children phoned home from Nashville, they were stunned and scared.

Nashville airport spokeswoman Emily Richard said the children never left the airport property and immediately were rebooked on return flights that night. Southwest said it has refunded their airfare.

The parents are just glad their children made it home safely.

"I never would have dreamed my kids would have got on a plane without me or their mom," James Brown said. "But they did. It was very scary, very scary. Luckily, they're OK."