 Chicago Express, operating as the ATA Connection, flew British Aerospace Jetstream 31 turboprops which were then replaced with Saab 340 turboprops.C8 was also the IATA code used when travel agencies were writing tickets upon Chicago Express routes, and booking travel between airlines not affiliated or owned by ATA.When the remains of Chicago Express (C8) were liquidated, the company was sold as Chicago Express, just as it read on the company's original airline operating certificate.