HONOLULU -- The air-fare war for interisland travel is heating up again.

Mesa Air Group's go! announced Friday morning that it would sell a $19 one-way ticket from Honolulu to Lihue, Kahului, Kona or Hilo. Hawaiian and Aloha airlines followed a few hours later with news that it would match the price.

The tickets for go! began selling on Friday. The tickets must be purchased by midnight Sept. 30 and used until Feb. 28.

go! began offering $19 fares when it first started flying in Hawaii in June. Prices since then have gone up to $39 for a one-way ticket. Hawaiian and Aloha airlines kept their prices in line with go! in many of the moves in the summer travel season.

"We've had a great response. It may be our best day of sales yet," said Joe Bock of go! Airlines.

The move launched a war of airfares and words.

Go! called their new offering "Hero fares." It is a play on a newly formed group HERO, Hawaiian Employees Repelling Orstein. Jonathan Ornstein is go!'s chief executive officer.

That didn't go over too well with the group HERO, which claimed it represents workers from all four interisland airlines.

The top two Hawaii airlines blasted go! for its tactics.

"It's clear that go!'s latest action is a direct attack on the livelihood of Aloha's employees," Aloha Airlines said in a statement.

"If it wasn't clear to everyone before, it should be now that Mesa (go!'s parent company) is trying to eliminate competition in Hawaii," a written statement from Hawaiian Airlines said.

Meanwhile Island Air has stayed out of the fare war. It was offering one-way fares up to $100.