It was shown by Trew and
Zvengrowski that the only Grassmann manifolds that are stably parallelizable as
real manifolds are G1(F2), G1(R4)≅G3(R4), and G1(R8)≅G7(R8) where
F = R,C, or H, the case F = R having also been previously treated by several
authors. In this paper we solve the more general question of stable parallelizability of
F-flag manifolds, F = R,C, or H. Only elementary vector bundle concepts are used.
The real case has also been recently solved by Korbaš using Stiefel-Whitney
classes.