Incident No. 21 — 29 June 1947, 1645, Des Moines, Iowa.
The observer, a bus driver, reported observing thirteen objects at 1200 ft altitude, traveling in a straight line in file at 300 MPH. The objects were elliptical in form "inverted saucer", 12 ft thick, 175-250 ft in diameter, dirty white, and made a sound like an electric motor or dynamo. There was no further information supplied except that the observer stated they looked like dots in the sky.
AMC Opinion: These objects were seen just outside Des Moines, and were flying toward Des Moines. If they were not ordinary objects mistaken for something else by the observer, but were really unusual aircraft, it seems almost certain that someone else would have also reported them. There is insufficient information for a proper analysis.