low altitude flourescent light

I was walking to the garbage bin at the apartment complex where my friend lives.
I looked up to the sky facing the west.   When I thought a low flying small airplane was heading towards the Hayward Aiport which was roughly 5 miles from where my friend lives.  It was rectanglar in shape and was lighted like a white flourescent light bulb.  It made no noise whatsover. 
It glided on a downward slope as if it was hugging the terrain, and then disappeared into thin air.  I realized it wasn't a plane when it made a dip as it descended and no other lights were visible, it seemed to be like a flying flourescent piece of white plastic.