AUSTIN (KXAN) – It’s not just people that are stranded by Southwest’s flight cancellations — their luggage is too.

It’s a situation many have found themselves in: How can my bag reach my destination when I couldn’t get on a flight?

Carson Pearce, an aviation expert, says the standard operating procedure for airlines is something called “positive passenger bag-matching,” or PPBM.

“In theory, no bag should leave the airport without the passenger being on the airplane,” said Pearce, who leads the aviation science department at Texas A&M University – Central Texas.

Pearce said airlines follow PPBM for security reasons.

“That’s because they don’t want somebody to come in, book a flight… in a worst case scenario, put a bag on, then they leave and go somewhere else, and the bag goes, boom,” he explained.

But he said when you’ve got thousands of canceled flights and corresponding luggage, employees can’t keep up with matching your bag to you.

“When you’re in a massive meltdown, such as what is being experienced by Southwest, what you have is thousands of bags,” Pearce said. “All of a sudden a flight pops available, they see that tag on there; let’s just say it’s Austin, throw it on and get it out of here because there’s no more room at the end. We don’t have any other place to put it.”

Southwest Airlines confirmed to KXAN that tagged bags are forwarded on. Once they arrive, if a passenger doesn’t claim them, the company starts trying to reunite the bag with the customer.

You can submit a ticket for baggage help for Southwest through this website.

Southwest also said it’s tricky to remove a checked bag from the plane once it’s loaded, saying “the plane has to move eventually, even if customers aren’t on it.”

“It’s very cumbersome to remove checked baggage from the aircraft once it is loaded. The plane still has to move eventually, even if Customers are not on it. The aircraft is expected to be somewhere else and those bags are expected to be in that location too. It’s a highly complex process that is a part of how our Network works in concert,” the airline said in a statement.

In a later email clarifying their statement, the airline explained:

“During irregular operations, such as a winter storm and flights are canceled, we do our best to reunite Customers with their bags. However, once flights begin moving, we are focused on getting our Customers and their bags moving too. In situations like the ones we are finding ourselves in today, bags are tagged for a certain destination and those are forwarded onwards. Once it arrives in that destination city and the Customer does not claim it, we begin the process of reuniting the bag and the Customer.”

Pearce said while all airlines follow the PPBM method, how an airline deals with overload can differ.

“Southwest says, ‘If we have a plane that’s delayed and the bags are on it… we leave the bags on it. Now, most airlines’ procedures that I’m aware of… they remove the bag from the plane. If that person isn’t on it, they remove it,” Pearce said.

Joshua Mobley ran into the problem in Denver.

After being canceled and rebooked a few times, he said a Southwest agent assured him his next flight wouldn’t be canceled.

“I’m like, ‘Okay, cool. Check my bag… Worst mistake of my life,” Mobley said.

That flight ended up being canceled, but Mobley couldn’t get his bag back.

“If you check into a flight with your bag and it’s canceled, there should be a way to you to retrieve your bag,” he said.

Mobley ended up finding the second-to-last seat on a United Airlines flight to Austin and decided to pay the $500 for a ticket.

Now, he’s in Austin, but his Southwest bag isn’t.

Mobley has a GPS tracker in it. He pulled up the app on his phone and showed KXAN the suitcase’s route.

On Wednesday, his app pinged his suitcase in Seymour, Texas.

He said Southwest staff informed him his suitcase didn’t make a flight, at all — it’s on a UPS truck headed to Austin.

“I learned my lesson. I’m always gonna keep up trackers in my bags. Especially with Southwest,” Mobley said. “People are screwed. I feel sorry for people, especially people with kids and elderly people.”

Mobley said he will be back at the Austin airport for a third time on Thursday, hoping his bag with all his work gear will be among the dozens between crowded carousels.

“Hopefully they learned from this and they don’t have anything close to this kind of thing,” he said. “I’ve never seen this in my life. Ever.”