Well duh, don't we all these days? But according to this article in the NY Times (free reg. req'd), "Data from the department's Bureau of Transportation Statistics last week showed that this was shaping up to be the worst year for departure delays since 2000. In the year through June, nearly one in five flights, or 17 percent, left airports late." And it's even worse for some flights:
Tell attendees to bring a couple of good books to read—they may be at the airport for a while.