make_date() and make_datetime()

flights |> 
  select(year, month, day, hour, minute) |> 
  mutate(
    departure = make_datetime(year, month, day, hour, minute),
    dep_date = make_date(year, month, day)
  )

## # A tibble: 336,776 × 7
##     year month   day  hour minute departure           dep_date  
##    <int> <int> <int> <dbl>  <dbl> <dttm>              <date>    
##  1  2013     1     1     5     15 2013-01-01 05:15:00 2013-01-01
##  2  2013     1     1     5     29 2013-01-01 05:29:00 2013-01-01
##  3  2013     1     1     5     40 2013-01-01 05:40:00 2013-01-01
##  4  2013     1     1     5     45 2013-01-01 05:45:00 2013-01-01
##  5  2013     1     1     6      0 2013-01-01 06:00:00 2013-01-01
##  6  2013     1     1     5     58 2013-01-01 05:58:00 2013-01-01
##  7  2013     1     1     6      0 2013-01-01 06:00:00 2013-01-01
##  8  2013     1     1     6      0 2013-01-01 06:00:00 2013-01-01
##  9  2013     1     1     6      0 2013-01-01 06:00:00 2013-01-01
## 10  2013     1     1     6      0 2013-01-01 06:00:00 2013-01-01
## # ℹ 336,766 more rows