In June, airlines improved on-time performance from 2015

WASHINGTON — Airlines were running on time more often in June than they did last summer and travelers seemed to be finding less to complain about.

But that was before computer outages this month at Delta and last month at Southwest led to more than 4,000 flight cancelations, widespread delays and travel nightmares.

The Transportation Department said Wednesday that 78 percent of flights on major U.S. airlines arrived on time in June, up from 74.8 percent in June 2015.

The on-time rate slipped from May’s 83.4 percent mark, however.

Hawaiian Airlines and Alaska Airlines had the best on-time ratings. American Airlines had the worst.

Travelers filed 1,078 complaints with the government about all U.S. airlines in June, down from 1,567 a year earlier.