There's bike parking (last I heard) at the long-term parking lot on the ATS (most northern station).
I'd say it's a CTA issue, but CDOT often supplies CTA the racks. However, the City of Chicago Department of Aviation may own the CTA station, since it's on their property.
I'm interested in riding my bike to OHare to catch a plane. Anyone else do this? Main biggest concerns are locking bike up securely over the weekend and also the 8 or so blocks from terminal building to the Des Plaines River Trail. Any info appreciated!
I've done this. I took Higgins to what-ever-street-leads-to remote parking. I left it there for four or five days and took the tram to and from the terminal.
This is from a number of years ago. Bessie Coleman Drive has been widened. This was my route before the CTA started allowing bikes on the train.
Speaking as the guy who supervised the installation of the original bike rack inside the station (I rode the train to O'Hare with the contractors, who carried the U rack and their power tools) as a CDOT consultant more than a decade ago, CDOT is responsible for new installation, in coordination with the CTA, of course. I'd suggest emailing the department at email@example.com.
Last time I checked there was a large "wave" rack inside the station with space for six bikes. If more capacity is needed, it could be replaced with 4-6 U racks installed parallel to each other, perpendicular to the wall, which would provide space for 8-12 bikes.