这两个短语的意思是有区别的.behind time是指“迟到”、“误时”、“不及时”.例如：
We are behind time in seeing the movie.我们迟看了电影.
This plane is behind time.这趟航班晚点了.
behind the times是指“落后”、“不合时宜”、“跟不上时代”.例如：
That old man's ideas are all behind the times.那个老人的观点很陈旧.
My parents' views on marriage are a bit behind the times.我父母对婚姻的看法有点儿不符合时代潮流.