DAVID GREENE, HOST:
Good morning. I'm David Greene. That's the sound of Port City Sound. They're a barbershop quartet from Maine, performing on a U.S. Airways flight bound for New Orleans. During a delay, a flight attendant asked the group to sing to keep passengers from going stir-crazy. According to her post on YouTube, where the video has racked up over 3 million views, the passengers were awesome for the next five hours. It's MORNING EDITION. Transcript provided by NPR, Copyright NPR.