(CNN) -- Inspectors have found "nothing unusual" in the rest of Southwest Airlines' fleet of 737-300s after a football-sized hole in one of the jets forced an emergency landing, an airline spokeswoman said Tuesday.

The breach in the aircraft's fuselage caused a loss of cabin pressure. No passengers were injured.

The airline inspected its roughly 200 Boeing 737-300s overnight following the incident that forced Southwest Flight 2294 to make an emergency landing in Charleston, West Virginia.

A sudden drop in cabin pressure caused the jet's oxygen masks to deploy, but there were no injuries among the 126 passengers or the five-member crew.

Marilee McInnis, a Southwest spokeswoman, said the jets were inspected during non-operational hours overnight, and the cause of the incident remained unknown Tuesday morning. The airline is working closely with the National Transportation Safety Board to investigate the matter, she said.

Flight 2294 was at 34,000 feet, en route from Nashville, Tennessee, to Baltimore, Maryland, when the incident happened, McInnis said. See map of flight path »

"About 45 minutes into the flight, there was a loud pop. No one really knew what it was," passenger Steve Hall told CNN Radio. Watch as passenger describes watching the hole form »

The plane landed in Charleston at 5:10 p.m. after the crew reported the sudden drop in cabin pressure, which caused the jet's oxygen masks to deploy.

"We were seated about two rows back from the wing, and four rows back you heard this loud rush and your ears popped, and you could tell that part of the inside was trying to pull out," passenger Sheryl Bryant told CNN affiliate WBAL-TV upon arriving in Baltimore aboard a replacement plane.

"And it was crazy -- the oxygen masks dropped," she continued. She put her mask on her face, then helped her 4- and 6-year-old children with theirs, she said.

Bryant tried to stay calm and reassure her children, she said. Watch Bryant's account of acting brave »

"My kids and I, we prayed, and then we said, you know, life will be fine," she said.

Bryant praised the flight crew and ground personnel for keeping passengers informed and for giving clear instructions.

"We have a tremendous talent represented in the pilots and the flight crew," another passenger, Pastor Alvin Kibble, told WBAL-TV. "I think we need to value them far more than perhaps what we do. It's very easy for us to begin to take things for granted."

The damaged aircraft was still parked at Charleston's Yeager Airport on Tuesday, when NTSB officials arrived to inspect the plane, airport spokesman Brian Belcher said. A complete inspection could take one to two days, and investigators are expected to interview the passengers and crew as well, he said.

The airline is "doing things" for the affected passengers on Monday's flight, but McInnis would not say whether they would receive refunds.

Both the Federal Aviation Administration and the National Transportation Safety Board are investigating the incident, FAA spokeswoman Holly Baker said.

"There is no responsible way to speculate as to a cause at this point," Southwest said in a statement Monday night.

"We have safety procedures in place, and they were followed in this instance to get all passengers and crew safely on the ground," the airline said. "Reports we have are that our passengers were calm and that our pilots and flight attendants did a great job getting the aircraft on the ground safely."

CNN's Shawn Nottingham and Stephanie Gallman contributed to this report.

All About Southwest Airlines Inc. • Federal Aviation Administration • Charleston (West Virginia)