Continuing from my previous post, if I were to rearrange your entire quote, I might do it in the following way:

A new kind of virus has spread to millions around the globe and shown no sign of slowing down: people everywhere are becoming addicted to flight. The freedom and joy of flight! As Leonardo Da Vinci put it: "Once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."

In addition to what dvorakdan said, here are some more corrections:

- A colon can be used to introduce a quote, but never a semicolon.

- You should use quotation marks around a quote. I know this is a translation and not a direct quote, but we're talking about Key Hero; we can't follow the proper conventions for this situation within the small space given us.

- "The freedom of it, the joy" is a sentence fragment. You can use fragmentation if you really want to; it can be an effective style choice. However, for the sake of smooth reading, I would change it to "The freedom, the joy of it." Even so, it's still a bit unclear what "it" is referring to. Are freedom and joy referring to flight, or are they referring to the idea that people are becoming addicted?

Fortunately for us... is not a sentence. It isn't even clear why that is fortunate. And I don't think "Everyone, everywhere" is in any way "addicted" to flight. I would not be surprised if more people on the planet have never flown than have. And in that chunk of haves, there are probably plenty who have only flown once or twice. Nice words by Da Vinci though.