Most memorable "sightings" trip was to LA two summers ago.
On the ATL-LAX outbound, sat next to the head of Tyler Perry Studios (really nice Cuban guy, name escapes me now). Across the aisle was Hubie Brown, and Chris Webber was a few rows behind him.
I chatted with C-Webb for a bit on the way to baggage claim -- super nice guy. The next night was Game 1 of the 2009 NBA Finals, Lakers-Magic.
Two days later, I was on the same Alaska Airlines LAX-SEA flight with Celtic great Bill Russell. Man, is that guy tall!!!