Willys Jeep or "Willis" Jeep?

Above, a 1956 poster of the Willys Jeep family of vehicles.

A few months ago, I viewed a vintage newsreel of various gatherings of Willys Jeep groups and rallies of the 1950s.

In the film, the name Willys was pronounced as Willis. I thought that was odd, given the spelling and since I am relatively new to Jeeps, I never heard this before.

I was tempted to ask about the correct pronunciation of Willys, but never got around to it. Well, this evening, I spotted a Facebook thread on this subject.

One poster wrote:

Technically, John Willys pronounced it Willis, but most people say Willies.

Another wrote:

Old news reels also pronounce Grumman Aircraft as Grewman, and Lockheed changed the spelling of the name of the company because Mr. Loughead didn't like people mispronouncing the name as "loghead". Then there's the whole "Porsche" vs. "Porsh-a" thing. As for me it will always be a "Willies" Jeep...

Is it Willies or Willis? Well, the video below should settle the matter (or maybe not):