Here is what written on the site I found these. I guess “peculiarities” would be subjective. I’m not at my computer right now and I can’t get the link to copy on my phone but these came from The Internet Archives. There are several more there should anyone want to look at them. I think they’d make pretty cool wall hangings for the sim room.
“Aircraft recognition posters were used – in concert with other tools such as three dimensional scale models and film slides – by instructors to teach students how to identify and differentiate between Allied and Axis aircraft. The phrase "WEFT UP", seen on the right side of the posters, was a mnemonic listing six major aspects of aircraft design to focus on to aid in recognition. The letters stood for: wings, engine, fuselage, tail, undercarriage, and peculiarities. The stars next to each letter may indicate the prominence of each figure for each model of aircraft. The "MacArthur Names" included for Japanese aircraft refer to the "hillbilly" series of reporting names developed by the Allied Technical Air Intelligence Unit.
These posters were published by the Naval Aviation Training Division from October 1942 to April 1943 and the Bureau of Aeronautics in February 1944. The latter are labeled "U.S. Government Printing Office : 1944–O–572602". A distinct change in font is also noticeable between December 1942 and January 1943. It is most evident in that the latter uses an "O" character to represent a "0". Some minor mistakes in the format of designations, such as hyphen placement (e.g. "L4-A" instead of "L-4A") exist as well.
This collection of 120 posters comes from the Tri-State Warbird Museum and was scanned by the Cincinnati & Hamilton County Public Library. The title of each poster has been reproduced verbatim in the item name, but the correct format of the aircraft's manufacturer, designation, and nickname – if applicable – is included in the description.”