The jet, carrying 124 passengers, landed at the wrong airport in Branson, Mo., Sunday, seven miles away, on a runway about half the size of the intended destination.
A steep drop-off lurked beyond the Taney County Airport runway.
"[It was] very shocking when we exited the plane and saw the actual runway and how close we were to the edge of the runway," Poole told ABC News.
Passengers reported a sudden stop to the flight. Scott Schieffer says he could smell burning rubber from the plane's tires as they came to a halt.
"The brakes were applied forcefully. We were lurched forward a little bit. I was glad I had my seatbelt on in that case," Schieffer told ABC News.
The pilot spoke to passengers over the intercom after the landing, trying to calm their nerves.
"People know we are here and we will be taking care of you just as soon as we can," the pilot said, as recorded by a passenger on the plane. "Thanks again for your patience and I apologize."
Airline spokesman Brad Hawkins called the landing "uneventful," noting "all customers and crew are safe."
But the pilots are likely to be reprimanded for a mishap that could have been disastrous, ABC News aviation consultant John Nance said.
"There is a very high propensity for a collision, especially if you've got a large airplane making this mistake into a smaller airport," Nance said.
The Boeing 737-700 took off at Chicago's Midway International Airport and was supposed to land at Branson Airport. A relief plane later brought the passengers from the proper Branson airport onto Dallas.
The Federal Aviation Administration and National Transportation Safety Board are investigating the incident, which marks the second time in less than two months that a large jet landed at the wrong airport. In November, a Boeing 747 that was supposed to deliver parts to McConnell Air Force Base in Wichita, Kan., landed 9 miles north at Col. James Jabara Airport.
It's also the latest in a string of hiccups for Southwest. In November, a Southwest flight from Tampa to Raleigh dropped 10,000 feet after a cabin pressurization problem, making some passengers sick.
A July flight landed nose-first at New York City's LaGuardia Airport, setting off sparks and panic.
ABC News' Matt Hosford, Dean Schabner, ABC News Radio and the Associated Press contributed to this report.