As much as the speed of Zeppelins annoys me, staff have already made it clear they do not want air travel to make other forms of travel obsolete because it ignores terrain. Making zeps near the same speed as everything bar gear 7 trucks won't help accomplish that.

I just want them to be at least able to out speed someone on foot.

sprint speed is 5.62 with speed pants that goes to 8.98. Zep is 8 :( . If im gonna get a dub of wool and print a 7000 block craft at least let it be faster than walking.

I would be happy with 10

As snasycanuck said, Zeppelins can bypass terrain, which actually makes them faster than moving on foot as they don't have to run around mountains or swim over the ocean. Zeppelins also are notoriously messy crafts. Unlike ships, which largely get salvaged by the playerbase rather quickly, wrecked Zeppelins can stay up in the air for months or even years. Another issue is that Zeppelins are a really cheap way to transport goods from one place to another. If their speed was to be increased, they would make cargo ships and trucks useless.