A light pillar is an atmospheric optical phenomenon in which a vertical beam of light appears to extend above and/or below a light source. The effect is created by the reflection of light from tiny ice crystals that are suspended in the atmosphere or that comprise high-altitude clouds (e.g. cirrostratus or cirrus clouds). If the light comes from the Sun (usually when it is near or even below the horizon), the phenomenon is called a sun pillar or solar pillar. Light pillars can also be caused by the Moon or terrestrial sources, such as streetlights and erupting volcanoes.

Pillars of light
There are many potential explanations for sightings. We recommend eliminating the most common and mundane before jumping to less probable conclusions or you submit a report.
Resources
Flight & Marine Trackers
Live flight tracking maps are available for monitoring airline traffic and trajectories in real-time or historically around the world.
FlightAware
Flightradar24
ADS-B Exchange
Marine Traffic
Space Launches
Planned launches occur regularly all over the globe. These tracks can help identify the potential missions or launches in your area.
SpaceLaunchSchedule.com
SpaceFlightNow.com
RocketLaunch.Live
Satellite Trackers
Satellite tracking can also be done in real-time with the aid of tracking maps. They are also helpful for tracking Starlink launches.
Heavens Above
Space Weather
There are a number of sites which track solar flares, magnetic storms, and other events which are helpful for eliminating explanations related to astronomic phenomena.