American and Delta are having another fare war to Hawaii. Fares start at $335 round-trip and are available for travel this spring, late summer, fall, and next winter. United has some routes available for last minute travel this winter.
Travel is valid on Mondays, Tuesdays, Wednesdays, and Thursdays, from April 3 through May 24, and again from August 14 through January 2019. Travel to Hawaii appears to be blacked out between December 7, 2018 - January 6, 2019. Not all routes will be available for the entire travel period.