I just discovered a phone message from Mike saying that he missed one of his flights; he slept through boarding while at the airport.
I've done that before. I was waiting for a connecting early morning flight on the way back from a cousin's wedding in Savannah, GA last summer. I was exhausted and wanted to take a short nap, so I set the alarm on my cell phone and dozed off. An hour or two later, as I was sitting there sleeping through my alarm, everyone around me got up and boarded. I woke up just in time to see the plane taking off outside the window.
Luckily for Mike, there's another flight leaving two hours later so he won't get here too much later than he would have otherwise. When I slept through my flight, I had to spend an extra 12 hours with nothing to do at the Charlotte, NC airport.
Lesson learned: It's not smart to sleep at the airport; you can't count on being woken up. Wait and sleep on the plane; they'll be sure to kick you off at the end of your flight if you oversleep. ;)