You are also flying 'in the weather' .. making for a bumpier ride.
As a kid distinctly remember the diffence, being used to DC3s, cruising below 10,000 and the much smoother rides of a DC4, Britannia, Stratocruiser at well over 25,000, these planes were advertised to fly 'above the weather' for publicity and lure reluctant air-sick prone passengers.