data(airquality)
x <- airquality[, -1] # x is a regression design matrix
y <- airquality[, 1] # y is the corresponding response
all(!complete.cases(y) == is.na(y)) #--> TRUE
ok <- complete.cases(x,y)
sum(!ok) # how many are not "ok" ?
x <- x[ok,]
y <- y[ok]