I think the problem here is that you may have the wrong actor.

It sounds like you're thinking of "Love Field". Here's the review of it in Video Movie Guide 2000:

"LOVE FIELD (4 stars out of 5) Michelle Pfeiffer is a 1960s Dallas housewife who models herself after Jacqueline Kennedy. When President John F. Kennedy is assassinated, Pfeiffer decides she has to attend the funeral. On the way, she encounters Dennis Haysbert, a black man traveling with his daughter. Pfeiffer and Haysbert (in a role originally given to Denzel Washington, who left the picture) are superb."

-- Trip