there was a story in my company about one of our chief pilot (this was 30 years ago) who took of from brussels in caravelle, climbed to somewhere like FL300 above the field, throtled back to idle , glided to paris and landed in "le bourget" without touching the throttle.

this story can be thrue, the only restriction i see is ATC consideration, but this was 30 years ago, so ATC was not yet what it is now

cl/cd max for a caravelle is somewhere around 30 if my souvenir are correct. flying at Dmin is very uncofortable, but a slight increase in speed in order to keep you on the right sight of the drag eas curve won't penalise you a lot in cl/cd ratio

by the way if cl/cd max was 30 like I guess, the minimum angle of descent =arcsin (1/30), mean 1.90 degrees
a normal approach glide path is 3 degrees


most of people think airliners are flying like bricks, this is not thrue, a 747 is a wayyyyyyyyyy more clean than a cessna 172 for exemple.

cl/cd max for a 747 is somewhere around 20 and must be somewhere around 7 for a cessna