Originally Posted by
ugleeual
many times the longer layovers in Europe are due to limited service (not 7x a week) or a holiday period where the flights are reduced. The longer layovers in Asia are normally due to FAR rest requirements and augmentation as listed above.
PVG and PEK from EWR could still legally be done as three day trips, the company chooses NOT to schedule them that way so there is more of a departure window coming back in case of a delay.