Is that Dan Aykroyd standing at the ticket booth in the airport just before Stanley boards the plane to Detroit? He's in the background so look carefully.
I intend to live forever. So far so good.
I'm pretty sure that was him. It even sounded like him if you listen closely.
shareNo, the man playing the agent is not Dan Aykroyd, though he sounds and looks quite a bit like him. In 1989, during principle photography, Dan would've been younger and less puffy.
Also, Dan was in-demand as an actor and was busy with the films Driving Miss Daisy and Ghostbuster II that same year. It is highly unlikely that he would perform a blurry cameo without the filmmaker giving him proper credit.
The ticketing agent is an uncredited role played by an extra or an employee of American Airlines - as thanked in the credits.