In article ,
Mxsmanic wrote:

Kyle Boatright writes:

We flew commercial back to Atlanta yesterday from California after a
weeklong trip to San Francisco, Napa, and Yosemite. On the way home, I had
a window seat and was surprised on a couple of occasions at how close
1,000'
of vertical separation appears when you're looking out the window from seat
13A. When another airliner passes 1,000' right under you on a reciprocal
heading with a closing speed of over 1,000 mph, it looks CLOSE.

It IS close. Compare 1000 feet with the actual dimensions of the
airliner, which are an appreciable fraction of the separation distance
for larger aircraft.

And when you are flying 500 feet above CBAS ceiling and Approach is
vectoring inbound heavies 500 feet over your head, they look REAL BIG!!!