Landlocked, as an economic term, often implies a lack of major shipping ports. (The negative connotation of the term is arguably mainly from the higher prices for everything that has to be shipped in.)

For anyone expecting the economic definition (the more useful one) of "land locked", this map doesn't help, because the Great Lakes and the Mississippi River allow massive thriving sea ports for ocean going vessels - in states adjacent to them.

Edit: A map updated for major shipping ports would also be funnier, since Nebraska is extra fucked, in comparison. Although, there's no border taxes between the states, so the economic disadvantage of being land locked is also drastically reduced, for Nebraska, compared to the usual meaning.