WASHINGTON — Partly because of Hurricane Harvey, which shut down both major Houston airports for several days, canceled flights surged and delays increased on U.S. airlines in August.

The U.S. Transportation Department said Tuesday that the dozen airlines covered in its monthly air travel consumer report canceled 2.2 percent of their flights, up from 1.4 percent in August of last year.

The department said 77.1 percent of flights arrived on time, down from 77.6 percent in August 2016. The government counts a flight on time if it arrives within 14 minutes of schedule.

Hawaiian Airlines had the best rating among the 12 largest U.S. airlines, and Virgin America had the worst rate.