If you've ever seen a gossip blog or perused Twitter, you're probably aware that people absolutely love an airport celebrity sighting. The paps (and regular ol' travelers) chomp at the bit to capture a famous person in sunglasses and sweats, just trying to get from A to B in relative peace. It's not every day, however, that we see a celebrity belting out a popular song at the gate with absolutely zero shame. But that's exactly what happened last week in the Omaha airport. The celeb in question?…