It's never fun to be locked out -- whether it's from your house, your car, or a commercial airliner.

A Southwest Airlines pilot wound up crawling through a cockpit window on Wednesday after a customer inadvertently locked the flight deck door, the airline says.

Passenger Matt Rexroad told CNN he was getting ready to board a flight from San Diego to Sacramento when he saw the plane's pilot crawling through a window.

"During the boarding process, while other Customers and Flight Attendants were onboard, a Customer opened the forward lavatory door and inadvertently pushed the Flight Deck door closed (which locked) while the Pilots scheduled to operate the flight were preparing to board the aircraft," the airline said in a statement to CNN. "One of our Pilots unlocked the door from a Flight Deck window, and the flight departed as scheduled."

Rexroad took photos of the incident and posted them to Twitter.

"It is amazing that this pilot went above and beyond to get this flight out. We only left 8 minutes late. Impressive effort by Southwest Airlines," Rexroad said.

In response, Southwest Airlines wrote on Twitter, "Well that is definitely something you don't see every day."