Paul Patist had it right, the 23rd Headquarters Special Troops deception unit.
Here's front view of the bogus L-bird U-29, about half way down the page.
www.laynor.org/free_info.php
From a page introducing the book "Silent Soldiers", by Philip Gerard...
"Eisenhower's secret weapon—an elite troupe of 1,100 artists, actors, electronics wizards, designers, and writers drawn from the New York art world and colleges like the University of Chicago. These men created dazzling theatrical battlefield ruses, fooling the German high command into attacking the wrong place, defending the wrong bridgehead, even retreating from phantom attackers conjured by radio scripts, sound effects, a handful of convincing actors, and inflatable armored divisions.
Douglas Fairbanks, Jr. helped pioneer the tactics of this unlikely band of heroes, which included future fashion king Bill Blass, abstract painter Ellsworth Kelly, and artist Hal Laynor.
Drawing on recently declassified records, interviews, diaries, and letters, Secret Soldiers provides a fascinating and long-overdue tribute to the men who executed one of the greatest military deceptions of all time."
Some more photos of ruse constructs, a couple of L-5's...
www.philipgerard.com/new/pix.htm
One thing to consider, these guys didn't have as easy a life as could be imagined.
Sometimes they purposely drew fire in order to enable "real combat units"
to change position in the field.