Ending today, United Airlines offers roundtrip flights to Hawaii from select cities in the U.S. for as low as $414.60. (Click on "United.com" in the top line to see this sale; all taxes are included.) That's tied with our mention from last week and the lowest current rate we could find for select routes by $4. This price is valid on flights departing from Portland, OR, (PDX) to Honolulu, HI, (HNL) on October 7 with return on October 14. Roundtrip purchase is required. Book this travel deal today for travel through October 14. Click here to see more routes.