NavList:

No difference whatsoever on the glide ratio.To get maximum glide ratio you must fly at the optimum angle of attack and as long as you mainain that angle of attack then the glide ratio will be maximum.  With higher temperatures and/or lower atmospheric pressure the true airpspeed to maintain the best glide angle of attack will be slightly higher, say aboout 5 knots at 3000 feet but the indicated airspeed will be constant no matter the atmospheric conditions. Since the plane might be going a lilttle bit faster then it will be comming down a little bit faster but the glide ratio will stay the same, only Sully might have reached the river 5 or 10 seconds sooner, but would have splashed down in the exact same spot.

gl