Pass tasks to Todoist in the form airmail://message-ID(Message subject line)
The current integration results in tasks being created in Todoist with a long link back to the message in Airmail that is visible in the task's description. Using the format airmail://message-ID(Message subject line) would result in 'hot' (clickable) task descriptions made of the message's subject line only which, imho, makes things easier to visualize and work with in Todoist.
there is a workaround:
check this site: http://thesweetsetup.com/add-tasks-todoist-email/
simply put: in todoist: create a link to mail to a specific project (or the inbox in general). Use that link in Airmail to create a custom action: forward. as fowarding adress, use the link from todoist. Done