Dissimilar to the chemtrail pattern used 11-22-2009- preceeding the 3 day uncharacteristic fog that 'socked in' Chicago. Presumably for a cloaked joint DHS/AF air manuevers over the city. Thread: Chem Trails in Chicagoland
This time there were no north-south trails, only east-west extending more west(for the west to ease winds).
The flight pattern was 2 close trails(east-west) to the far north then two trails to the far south. This flight pattern was repeated moving towards the center of the city.
Altitude was 20-30,000ft? Higher than jets taking off from O'Hare and passing under the chemtrail jet, additionally there were jets cruising at a high altitude simultaneously as well.
Chicago Airspace Restriction NOTAM for the Chemtrail OP
The airspeed was much faster than 11-22-2009, very difficult to keep a 50X spotting scope on it. But the trails were created at the middle of the trailing edges of the main wings where there were no engines(to create a contrail). Yes, same jet for all of +dozen runs, red fuselage, aluminum wings, but moving way too fast for a tail ID or getting the aircraft's model.
Interestingly, the other high altitude aircraft created contrails which disappeared after a dozen 'aircraft' length's. The chemtrails were visible until they 'wafted' downward and spread out to combine into an even light haze. Whoever calculated the distance between trails did a perfect job for even distribution.