Korchmaros has classified (q+2)-arcs of PG(2,q), q even, which have a
transitive collineation stabiliser. In this paper we characterise (q 1)-arcs, q-arcs, and (q - 1)-arcs of PG(2, q), q even, which have a t
ransitive homography stabiliser as conics, translation q-arcs, and mon
omial (q - 1)-arcs, respectively (although for (q - 1)-arcs we need th
e hypothesis that q/4 is not a twelfth power). (C) 1994 Academic Press
, Inc.