Well, I use it that way. "Are you going?" "I may."

and

\May\, v. [imp. Might] [AS. pres. m[ae]g I am able, pret. meahte, mihte; akin to D. mogen, G. m["o]gen, OHG. mugan, magan, Icel. mega, Goth. magan, Russ. moche. ?. Cf. Dismay, Main strength, Might. The old imp. mought is obsolete, except as a provincial word.] An auxiliary verb qualifyng the meaning of another verb, by expressing: (a) Ability, competency, or possibility; -- now oftener expressed by can.