Keep your ear on the ball.

Year: 1969
Artist: Henry "Hank" Syverson
 
In the 1960-70s, Hank Syverson worked as an illustrator at J. Walter Thompson supporting various accounts, including Pan Am. In the late 1960s, he produced whimsical art for a series of ads which become the "GO" campaign which ran through the early 1970s.  Some of the ads were produced as posters in various sizes including 12 x 19, 21 x 22 and 28 x 48.
 
In this poster, the traveler is urged to keep your ear on the ball.