Delta Flight 1641 from San Antonio to Atlanta on March 8th had a couple of special passengers. There were two "special guests" flying in First Class, a couple of penguins from Sea World.
When the plane reached a cruising altitude, the captain allowed their handler to take them for a stroll up and down the aisle so that everyone could take a look at the cute, one-foot-tall penguins and get some great photos and videos.
So, I guess this answers the age old question. Penguins really can fly!