A printing system comprises a printhead to eject ink through an opening in a carrier plate to a deposition region. A print medium is held against a movable support surface by vacuum suction communicated through platen holes of a vacuum platen and transported through the deposition region. An airflow control system comprises upstream and downstream valves associated with the printhead, individually addressable channels for the vacuum platen, or both. The upstream and downstream valves are arranged to selectively block and allow airflow through an upstream side or a downstream side, respectively, of the opening in the carrier plate. Actuation of the upstream and downstream valves may be controlled based on a location of the print medium. The channels are arranged to selectively control the supply of vacuum suction to respectively corresponding columns of platen holes. Actuation of the channels may be controlled based on a size of the print medium.