Credit: Boeing247/Reddit.com

While aboard an Alaska Airlines flight leaving Burbank, Calif. bound for Seattle, Wash., a passenger looked out a window to see a handwritten message scrawled on what appeared to be a damaged area of the plane's wing.

"We know about this," the note said. Below the message, an arrow pointed down to a portion of the wing that appeared to be missing.

The passenger took a picture and uploaded it to social news website Reddit under the name Boeing247.

"The maintenance team for this Alaska Airlines 737 sure knows how to instill passenger confidence," Boeing247 said. "The method of communication here shows a unique level of professionalism."

Commentors on the posting weighed in on the airlines' unorthodox policy, including one Delta airlines operations employee.

"This is for the ground personnel meeting the arriving aircraft (parkers), who are required to inspect the ship and document any damage found on arrival. Marking apparent damage prevents reports from being filed at each station at which the aircraft arrives," the employee said. "Delta does not do this and we inefficiently file a report tens of times for damage that has already been documented, creating needless redundant emails and work."

Alaska Airlines spokeswoman Bobbie Egan said that the photo showed a permanent approved trim repair to the corner flap of the right wing, and that the plane was absolutely safe to fly.

"The small indent shown in the photo was reported multiple times in multiple flight crew reports. A maintenance technician wrote on the wing to acknowledge to flight crews that the repair was made, documented and that the plane was airworthy," she said.

Egan said the airline immediately removed the message from the wing upon hearing about it, and apologized for any alarm it may have caused.