Create an event using facebook.com or meetup.com and invite some interesting speakers. Drinks and snacks are always nice.
In description of your event remember to say who is the target audience. Beginners, intermediates, developers or maybe architects?
Good date is essential for high frequency. Morning and evening times are good idea.
Talk about your meetup as loud as possible! Reach out to community and we can publish your event on #announcements channel and tweet about it on @ApacheAirflow.