From what I understand, the issues with flying high on earth is that engines don’t work as well at high altitudes, and you get into ‘coffin corner’ where an air

From what I understand, the issues with flying high on earth is that engines don’t work as well at high altitudes, and you get into ‘coffin corner’ where an aircraft’s stall speed approaches the speed of sound (that is inconvenient for high aspect-ratio aircraft). These problems are not as challenging for electric aircraft flying in generally lower density atmosphere.