The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States....
We know the Tea Partiers loathe the word "welfare." Will that word swell like an angry cyst in the mouth of the Republican reading it and choke his/her windpipe?
Further, in clauses 13 and 14 of Article I, Sec. 8 (powers granted to Congress), this is specifically enumerated:
To raise and support Armies...;
To provide and maintain a Navy....
And nowhere in there, O ye self-appointed strict constructionists, does it mention anything about an Air Force.
We know, we know! You're only strict about what you don't like, particularly the "general Welfare." The Constitution doesn't specify the Federal Reserve either, and that one you want to abolish, because it isn't specifically enumerated among Congressional powers to create. But you can't cherry-pick the specifically unenumerated extensions of government without looking, well, hypocritical and inconsistent.