Hopefully. This once-useful adverb meaning "with hope" has been distorted and is now widely used to mean "I hope" or "it is to be hoped." Such use is not merely wrong, it is silly. To say "Hopefully, I'll leave on the noon plane" is to talk nonsense. Do you mean you'll leave on the noon plane in a hopeful frame of mind? Or do you mean you hope you'll leave on the noon plane? Whatever you mean, you haven't said it clearly. Although the world in its new, free-floating capacity may be pleasurable and even useful to many, it offends the ear of many others. who do not like to see the word dulled or eroded, particularly if the erosion leads to ambiguity, softness or nonsense.


Source: Strunk, White: The Elements of Style