United Airlines offers roundtrip flights to Hawaii from select cities in the U.S. for as low as $414.59, as provided by ShermansTravel. That's $44 under our mention from two weeks ago and the lowest price we've seen for these airfares this year. It's also a current low for select routes by $22. This price is valid on flights departing from Portland, OR, (PDX) to Honolulu, HI, (HNL) on September 7 with return on September 11. Roundtrip purchase is required. Book this travel deal by August 4 for travel through October 18. Click here to see more routes.