A ventilation module for a film stretching system for heating or cooling plastic film webs having the following features: - the ventilation module comprises a film entry region and a film exit region, the plastic film web being movable in the withdrawal direction within the ventilation module in a transport plane from the film entry region in the direction of the film exit region; - at least one first outlet nozzle arrangement is provided between the film entry region and the film exit region and is designed to blow air in the direction of the plastic film web for the purpose of heating or cooling; - the at least one first outlet nozzle arrangement comprises at least one outlet nozzle, the at least one outlet nozzle extending with its longitudinal direction transverse or perpendicular to the withdrawal direction of the plastic film web and being oriented in parallel to the transport plane; - at least one first return system having at least two extraction channels (10a, 10b) is provided, which extraction channels each have an intake region (11a, 11b), the at least one first return system being designed to extract air via the extraction channels (10a, 10b); - the at least one first return system is arranged between the film entry region and the film exit region; - the at least one outlet nozzle of the at least one first outlet nozzle arrangement and the at least two intake regions (11a, 11b) are arranged on the same side of the transport plane; - the at least two intake regions (11a, 11b) are distanced from one another in the withdrawal direction and are oriented in parallel to the transport plane, the at least two intake regions (11a, 11b) extending with their longitudinal direction transverse or perpendicular to the withdrawal direction of the plastic film web; - the at least one outlet nozzle of the at least one first outlet nozzle arrangement is arranged between the first and the second intake region (11a, 11b) in such a way that the at least one first intake region is arranged in the withdrawal direction of the plastic film web exclusively before the at least one outlet nozzle, and the at least one second intake region in the withdrawal direction of the plastic film web is arranged exclusively after the at least one outlet nozzle, characterized in that the at least one first outlet nozzle arrangement comprises a plurality of nozzle boxes (20b, 20c, 20d, 20e, 20f); and - a predominantly or completely air-impermeable cover plate arrangement, which runs in parallel to the transport plane, is situated between two nozzle boxes (20a, 20b, 20c, 20d, 20e, 20f) or at a distance from two nozzle boxes (20a, 20b, 20c, 20d, 20e, 20f), whereby two adjacent intake regions (11a, 11b) of different outlet nozzles (8a, 8b, 8c, 8d, 8e, 8f) are delimited in respect of their extent. - the ventilation module comprises a film entry region and a film exit region, the plastic film web being movable in the withdrawal direction within the ventilation module in a transport plane from the film entry region in the direction of the film exit region; - at least one first outlet nozzle arrangement is provided between the film entry region and the film exit region and is designed to blow air in the direction of the plastic film web for the purpose of heating or cooling; - the at least one first outlet nozzle arrangement comprises at least one outlet nozzle, the at least one outlet nozzle extending with its longitudinal direction transverse or perpendicular to the withdrawal direction of the plastic film web and being oriented in parallel to the transport plane; - at least one first return system having at least two extraction channels (10a, 10b) is provided, which extraction channels each have an intake region (11a, 11b), the at least one first return system being designed to extract air via the extraction channels (10a, 10b); - the at least one first return system is arranged between the film entry region and the film exit region; - the at least one outlet nozzle of the at least one first outlet nozzle arrangement and the at least two intake regions (11a, 11b) are arranged on the same side of the transport plane; - the at least two intake regions (11a, 11b) are distanced from one another in the withdrawal direction and are oriented in parallel to the transport plane, the at least two intake regions (11a, 11b) extending with their longitudinal direction transverse or perpendicular to the withdrawal direction of the plastic film web; - the at least one outlet nozzle of the at least one first outlet nozzle arrangement is arranged between the first and the second intake region (11a, 11b) in such a way that the at least one first intake region is arranged in the withdrawal direction of the plastic film web exclusively before the at least one outlet nozzle, and the at least one second intake region in the withdrawal direction of the plastic film web is arranged exclusively after the at least one outlet nozzle, characterized in that the at least one first outlet nozzle arrangement comprises a plurality of nozzle boxes (20b, 20c, 20d, 20e, 20f); and - a predominantly or completely air-impermeable cover plate arrangement, which runs in parallel to the transport plane, is situated between two nozzle boxes (20a, 20b, 20c, 20d, 20e, 20f) or at a distance from two nozzle boxes (20a, 20b, 20c, 20d, 20e, 20f), whereby two adjacent intake regions (11a, 11b) of different outlet nozzles (8a, 8b, 8c, 8d, 8e, 8f) are delimited in respect of their extent.