"It reminded me of the character Birdperson from the show Rick and Morty, only a LOT scarier!" - Unnamed Alleged Witness, April 2017
The Chicago Phantom is a case which began on April 10th 2017 when an alleged sighting of a winged humanoid in Oz Park, Chicago by an unnamed person was reported on by Manuel Navarette of the UFO Clearing House website under the title "Flying Entity, possible Mothman sighting seen in Chicago, Illinois".
These supposed sightings continued to be sent to and reported on by the UFO Clearing House, MUFON (Mutual UFO Newtwork) and the paranormal blogger Lon Strickler of Pennyslvania who seems to have widely popularized the case. Descriptions within the sightings were varied. Lon Strickler directed readers to his email so that supposed witnesses could send him their stories of winged humanoids in Chicago. He put together an interactive map of 59 alleged sighting locations and established a Chicago Phantom Task Force to share the sightings he received with a select group of researchers. Other investigators researched the case by going off the data released to the public.
Allison Jornlin and Kimberely Poeppey, both of Milwaukee, traveled to Illinois in 2017 to investigate The Chicago Phantom. Allison visited each of the 59 alleged sighting locations and conducted research as well, ultimately coming to the conclusion that a large percentage of the sightings were inaccurate, inconsistent or most likely hoaxes.
Despite news publications and websites referring to the case as the "Chicago Mothman", the sightings had no connection to the legendary Mothman of 1966-67 other than superficial details. It should be noted that this case happened to coincide with the 50th anniversary year of the 1967 Mothman events as well as the lead-up to the release of The Mothman of Point Pleasant (2017) Documentary.
Though many winged humanoid sightings in the Illinois area around 2017 could be genuine mysteries and anomalies, several of them are highly doubt-able. Books were released on the sightings in December of 2017 and in 2019. The case was also summarized in the Small Town Monsters documentary Terror In The Skies (2019).
Sources:  https://ufoclearinghouse.wordpress.com/2017/04/10/flying-entity-possible-mothman-sighting-seen-in-chicago-illinois/  https://mysteriousuniverse.org/2017/12/mothman-problems-an-interview-with-allison-jornlin/  Mothman: Evil Incarnate (2017) by Loren Coleman (pg 9-16 & pg 62)  Terror In The Skies by (2019) Small Town Monsters
2011 - Three Winged Humanoid Sightings (Stand-Alone):
In 2011, a couple in Chicago, Illinois made a report to the UFO Clearing House claiming to have photographed a winged humanoid. The somewhat blurry image provided appeared to show a winged object or entity in the distance. Two other sightings of winged humanoids in Chicago were reported that same year. These three sightings were stand-alone cases that took place long before the social phenomenon of "The Chicago Phantom" began but nonetheless the 2011 sightings are often paired together with the 2017 phantom case.
Source: UFO Clearing House - https://ufoclearinghouse.wordpress.com
Afterwards - The "Lake Michigan" Sighting Collection:
Tobias & Emily Wayland of The Singular Fortean Society continued to collaborate with Lon Strickler and the Chicago Phantom Task Force. They cataloged winged humanoid sightings beyond 2017 and expanded the area to include not just Illinois but also Missouri, Indiana, Michigan, and Wisconsin. They also expanded the time-frame to include not just 2017 but from the late 60's till the present day.
Tobias in his writings has held to the idea that these sightings were of a Lake Michigan "Mothman" or at least in some way related to the classic 66-67 case. He received alleged sightings, interviewed supposed witnesses and traveled to reported sighting locations. Despite criticism, he continued to investigate the case and was convinced in the possibility that winged beings, in whatever form, were lurking about and flying around the Lake Michigan area.
Source: The Lake Michigan Mothman (2019) by Tobias Wayland
Skepticism and Criticism:
Paranormal researchers and skeptics have pointed out suspicious elements of the case like the overly poetic lofty word choices of the supposed witnesses and the provable falsehoods within some stories, such as describing the moon at a time when the moon wasn't out or describing seeing a creature in great detail as it jumped off an extremely tall building (Willis Tower) from which it would be just a speck to the viewer. Another point of criticism was that many of the locations were in high traffic areas of the big city with many security cameras present yet the creature remained somehow hidden. Sam Maranto of MUFON also revealed that a significant amount of alleged sightings were sent online from the same IP address.
In an interview with Mysterious Universe in December of 2017, Fortean researcher Allison Jorlin said "Unfortunately, my opinion is that most of the reports are fraudulent, which is so disappointing because I love monster-hunting." She continued, "Cited weather conditions or moon phases in the accounts do not line up with the facts. I’ve also discovered inconsistencies in witness statements compared to what I saw at the locations."
She summarized by saying "There is an over-reliance on witness reports that have not been corroborated with location, weather, or other factual data that is easy to verify. The problem is then that anyone could make something up and waste investigator time while there are real mysteries out there that remain unexplored."