Posted on March 22, 2018December 8, 2018 by Erik Chipchase fokker_d_xxi_netherlands_by_mercenarygraphics The Fokker D.XXI (D.21) fighter was designed in 1935 for use by the Royal Netherlands East Indies Army (KNIL) air service. As such it was designed as a cheap but rugged small plane, which had respectable performance for the time of conception.