ORIGINAL: dick Hanson

How kum--
I see lots of lip service given to air being deflected down /low pressures above /high pressure under etc., yet none of the comments are including a rather easily seen characteristic of air (a gas) which is simply --compression.
Look at for example -- a plane going lickety split (fast) which is suddly janked into a vertical attitude -- skidding forward . It can be done and is done routinely now even at full scale airshows .
So - air IS compressed ahead of the skidding craft - call it bow wake , call it watermelon -whatever - it is air being compressed .
Whay not just state the obvious--


planes fly on compressed air ---


a really big plane compresses more air -simply because the air can't get out of the way fast enough.
As the plane slows - the air can get out of the way but to fly - the bubble of higher pressure must be in effect.
Unless -you really believe the low pressure above the wing sucks the plane into the air----