Is it possible to plot time( such as 9am, 9.30am, 10am, etc) vs duration (450mins, 500mins, etc) in R?

Is it possible to plot time( such as 9am, 9.30am, 10am, etc) vs duration
(450mins, 500mins, etc) in R?

I'm relatively new to R and i've been trying to plot a scatterplot for
time vs duration. I have 2 csv files ,one for times ranging from 9am to
2am in 30 min intervals and the other in minutes.
I tried doing:
departure.time <- read.table("~/departure time.csv", quote="\"")
View(departure.time)
travel.time <- read.table("~/travel time.csv", quote="\"")

View(travel.time)
plot(departure.time, travel.time, main="Variable Travel Time",
xlab="Departure Time", ylab="Travel Time in Minutes", pch=19)
and got the error :
Error in xy.coords(x, y, xlabel, ylabel, log) : 'x' and 'y' lengths differ
Any advice? Thank you!