What is this strange cutout in Class B of Kansas City International Airport?
There are in fact two airports in the cutout:




An unmarked field (A in top map) just east of Platte City (see below) that corresponds to the NW limit of the cutout. Note that this edge of the cutout appears to parallel the main runway at MCI.





The private Elton Field (B in top map). In the image below, field is boxed in red and runway in blue.




And there's also the VFR reporting point over north Platte City