NA on the first of every data set while doing time series

enter image description herets <- readxl::read_excel("Air_Carrier_Traffic.xlsx", skip= 1) %>% ts(,frequency=12, start=c(1996,1), end= c(2022,4))

ts<- na.locf(ts) summary(ts, na.rm= TRUE) ts

I did this but still couldnt totally remove NA as i change to other year, the NA will only appear at the first.