Question

why aircraft have small window​

Answer 1

Answer:

Windows on aircraft are small to maximise the areas of hull between them, to increase the strength of the air frame. The air frame would be stongest if the hull had no windows. Large windows were the cause of the loss of several De Havilland Comets (the world's first, UK built, commercial jet aircraft) as the strain put on the hull due to pressurisation caused metal fatigue in the slim areas of hull between windows, leading to at least two catastrophic ruptures at altitude.