Why are two blankets warmer than one which is double the thickness of each?

Two blankets create more warmth than one thicker blanket due to the trapped air between them, which acts as an insulator. This layer of air reduces heat loss, as it prevents the transfer of cold air from the outside. Additionally, the two separate layers allow for better regulation of body heat, whereas a single thicker blanket may not provide the same level of insulation efficiency. Thus, the combination of air pockets and heat regulation makes two blankets warmer than one thick one.