So, i decided to sort of redraw another episode scene.
 
Although pegasi can touch clouds, raw clouds are not exactly suitable for ponies to walk on, but pegasi and hippogriffs have known for centuries how to prepare slightly harder clouds that are suitable for building and for walking on - such building clouds are usually set atop a mass of raw clouds, since building clouds have a tendency to slowly sink to the ground if they are let out in the sky by themselves.
 
Cloudsdale (Parsabrapura), like all cloud cities, has its own area designed for airship landings, at a lower level than the city itself - ponies and goods are taken either through stairs or ramps.