Conversion of airflow signal into 1-D as a input for CNN
The airflow signal is usually respiratory input in a polysonogram. If your input files are .EDF files, then you need to extract the airflow signal only, which is a 1-D signal. I think there are many implementations of edfread.m that are available online.

https://www.mathworks.com/matlabcentral/fileexchange/31900-edfread