During a busy holiday flying season it's not uncommon to have delays. Mechanical failure, bad weather, and other factors can all make traveling a huge headache.

So it's not too unusual that a Southwest Airlines flight ran into difficulty on its way to Dallas, TX. What was weird, however, was why it needed to turn around and head back to Seattle.

Flight 3606 was a special flight, carrying with it "life-critical cargo" that would mean another chance at life for a patient in a Seattle-area hospital. Unfortunately, someone misplaced that cargo.

A human heart, designated for transplant, was supposed to be removed from the plane, but it was left in the cargo hold. It wasn't until the flight had taken off again for Dallas that authorities realized what had gone wrong.

The captain reportedly got on the intercom and explained to passengers what was going on. Many were surprised, but most were "happy to save a life" according to passenger Dr. Andrew Gottschalk.

It seems like a comedic situation, but hearts for transplants are only viable for a short time. Doctors had to race against the clock to get the heart back to where it needed to be.

The airline hasn't said much about the issue, but did release a statement:

"We brought in a different aircraft to continue the flight to Dallas, with an estimated delay of approximately five hours. Nothing is more important to us than the Safety of our Customers and the safe delivery of the precious cargo we transport every day."

Nothing is known about what happened to the organ, or if the operation was a success. It's clear that they had no choice but to turn around, but no one has taken responsibility for the mix up in the first place.