LiMing's family are going to Suzhou by plane还是LiMing's family is going to Suzhou by plane.为什么

用单数：is going to
family表示“家庭”或“家人”,是集合名词,若视为整体,具有单数意义,若逐个考虑其个体,则具有复数意义.如：
His family are all tall.他家的人都很高.
His family is very large [big].他家是个大家庭.为什么这句话的意思是：李明的家人要坐飞机去杭州。family在这里是家人的意思。参考上次回答family视为整体，具有单数意义