Marvel at the science and engineering that keeps these planes flying, and remarkably safely:
How many flights are in the air at once? NOAA estimates that 5,000 planes are in the sky over the United States. On any given day, more than 87,000 flights travel through US airspace… globally estimates seem to be that there are around 8,000 – 13,000 though I didn’t happen to find an authoritative source.
This youtube shows the dots in motion:
This youtube works better in a larger view — those planes are just too dang small, but it has better resolution.
The Guardian has a very nice display of current flights (using realtime data) to celebrate 100 years of passenger flights (from January 2014). It shows the top image in motion.