Ken Hubbs was voted National League Rookie of the Year in 1962, the Cubs' second straight RoY (Billy Williams won it in 1961).
Just 22 in 1963, Hubbs regressed a bit offensively, but the Cubs had much hope that he'd be their second baseman for years to come. He was outstanding defensively and his size -- 6-2 -- led them to believe that he'd put on some muscle (he was listed at just 175 pounds) and hit for a bit of power. In some ways, he was a Ryne Sandberg prototype.
Hubbs had a fear of flying, and since airplanes were becoming the mode of travel for virtually all baseball road trips, Hubbs took flying lessons to try to conquer his fear. On February 14, 1964, not long after receiving his pilot's license, he took off from an airport in Provo, Utah, in a snowstorm. The plane crashed and Hubbs was killed.
The Cubs honored him in a pregame ceremony before Opening Day, as reported by Robert Markus in the Tribune:
The body of Ken Hubbs has lain at rest since that tragic, snow-shrouded day in February when he went down into a frozen Utah lake at the controls of his single engine plane. Yesterday in Wrigley field, they laid his memory to rest. While the competing Cubs and Phils stood at attention, heads bowed, along the third and first base lines, the opening day crowd of 18,868 rose for a minute of silent prayer. The storm clouds overhead gave an extra aspect of gloom to the proceedings. And then, suddenly, it was not routine. As the announcer intoned, "Amen," a sudden gust of wind raised a whirlpool of dust over the second base area where Kenny Hubbs performed so brilliantly for the Cubs. Then it was gone... just as Hubbs is gone.
The Cubs lost that game 10-8 and, after having finished over .500 in 1963, regressed to a losing season (76-86) in 1964.
I have a recollection from the time that the Cubs had intended to retire Hubbs' No. 16, but I can't find any specific references to that anywhere. I have read in recent years that they did promise not to reissue No. 16, but only for 1964. Yosh Kawano, Cubs clubhouse manager who, among other things, was responsible for assigning numbers in those days, kept No. 16 out of circulation until 1970, when it was given to Roger Metzger.
The Topps Company issued a special "In Memoriam" card in honor of Hubbs, which is the image at the top of this post. The entire card is below; click to embiggen.