Luckily the Plane was flying at a higher altitude than the drone

I was out playing doggie soccer with my dog on the deck and heard a plane so I looked up to see the plane and luckily the drone was lower than the plane or else they would have collided because of their paths. However, it is true that drones are usually (but not always flying under 2500 feet in altitude) and the plane was 4000 to 5000 feet above sea level (I knew this because I'm basically at sea level or a couple hundred feet above here on the coast where I live near San Francisco.

However, the drone was unmistakable because it made little flashes as the rotors hit the sunlight and reflected the sun back at odd times and the other reason i know it was a drone because it made no sound at all which also was interesting to me.

So yes, there are long term flying drones here in California as well. I couldn't be sure of the size simply because of not being completely sure what altitude it was at and because if you are not sure the altitude and you are not sure the size you might know because of no sound that it is likely electric but it is hard to establish the size of it because it was flying somewhere between 1000 and 2000 feet most likely.

However, I know from being a pilot in training flying Cessna 152s and Cessna 170s in the 1980s that most pilots are required to fly above 2500 feet just for safety after they take off from a runway. This gives you more time to recover if anything goes wrong while flying after takeoff like engine sputtering, running out of fuel or wind sheers and the like etc. 

But basically if the drone and the plane had been at the same altitude they would have collided. This is why I'm writing this in the first place.