Why is the filed altitude for flights taking off late always say “UNSPECIFIED?”
flightaware.com/live/flight/ASH7 … /KCOS/KORD
flightaware.com/live/flight/UAL6 … /KLGA/KORD
flightaware.com/live/flight/EGF4 … /KDTW/KORD
flightaware.com/live/flight/AAL1 … /KMCI/KORD