Birds fly. It's kind of their thing.
~Tim Lucas

This type of bird watching generally involves standing at a fixed location during the morning hours watching a directional flight of songbirds - most of which are considered to be nocturnal migrants. This page touches on some theories on why these flights occur, flight-specific identification tips, known hotspots, ideal conditions and more. 

Papers: 

Morning flight behavior of nocturnally migrating birds along the western basin of Lake Erie (2018):

• However, the orientation of morning flights was similar following nights with drifting and non-drifting winds, suggesting that birds on any given morning were not necessarily re-orienting as an immediate response to drift that occurred the previous night. Given the topographical characteristics of our observation area, the west-northwest movement of birds in our study is likely best explained as a more complex interaction...

Detoured flight direction responses along the southwest coast of Lake Erie by night-migrating birds (2019):

• We found that even when winds were energetically favorable for a lake crossing, many [nocturnal] migrants still routinely displayed deviated flight directions that approached paralleling the coastline.

The spring reverse migration of landbirds in the Pelee region: 2010-2012 (2013):

• The spring reverse migration of landbirds (i.e., birds flying in the direction opposite to be expected), within the Great Lakes region is controversial because it is not understood if the extent or reversal of flight direction in spring is truly a change in migratory patterns or a brief anomaly. It is also not clear what the fitness and community level impacts are. My objective was to determine what and how weather influences reverse migration and to determine which species and families of birds participate the most frequently in this form of flight.