Since the existing answer here wasn’t totally clear, and this is the top hit for “airflow landing time” I went to the chat archives and found the original answer being referenced here:
Maxime Beauchemin @mistercrunch Jun 09 2016 11:12
it’s the number of hours after the time the scheduling period ended
take a schedule_interval=”@daily” run for 2016-01-01 that finishes at 2016-01-02 03:52:00
landing time is 3:52
https://gitter.im/apache/incubator-airflow/archives/2016/06/09
It seems the Y axis is in hours, and the negative landing times are a result of running jobs manually so they finish hours before they “should have finished” based on the schedule.