greetings to you. i had a helicopter accident last night. i even had a cop asking if im good and peeling off like he knew about me. then two helicopters passes happened. Recently im curious about low flying aircraft and helicopters in my area in general.  i started noticing things like this helicopter had a white underbelly. a low flying plane had three white lights in a triangle and the forward one did not seem to be its head lights. there was even a off color white light like a hot air balloon. so without ranting i will give you this link i found on aircraft. it seems to be military but its a peace of the puzzle. happy reading!

https://fas.org/irp/doddir/army/fm3-01-80.pdf

update: i found a few interesting internet pages with helicopter pics. you may comment if you seen one harassing you. 

helicopters from new york and los angeles area :

https://edc.nyc/sites/default/...ntificationSheet.pdf

https://localwiki.org/la/Ident...t_see_in_Los_Angeles

helicopters by color! :

https://commons.wikimedia.org/...Helicopters_by_color