Airmail now allows you to set reminders ("remind me if no reply") on the outgoing messages. You will get notification if the recipient does not reply to your email on the scheduled time.
It reminds you at that set time if the message is not replied to before the specified time.
You can toggle this feature ON from the composer itself as shown in the picture below.
Where do I see all my reminders?
You can see all the sent emails listed in the
Reminders folder that is available in the sidebar as shown in the screenshot below.
Why I am not seeing my Reminders folders?
Please make sure that you have selected it to appear in the sidebar as shown in this article.
Please feel free to reach out for any questions.