I think we are using a virtualenv to install the Airflow dependencies. Can you check if the
/opt/bitnami/airflow/venv directory exists? I'm pretty sure it does, but I don't have a machine to check it myself at this moment, sorry.
If that folder exists, you can load it and check the installed packages running the next commands (note there is a dot+white-space at the beginning of the first command)
Regarding the question of adding your custom classes, maybe you need to install them as part of the virtualenv, and that once you have loaded it in the console, you can try to import it with the next command
python -c "import my_module"
But it is a good idea to ask the Airflow developers about this as well, just in case I'm missing something here.