Interisland fares are on sale again.

The new carrier, go!, dropped one-way fares to the Neighbor Islands to as low as $29 yesterday, and the discount was immediately matched by Aloha Airlines and Hawaiian Airlines.

Go!, a unit of Phoenix-based Mesa Air Group, touched off a price war when it opened for business in Hawai'i on June 9. Lower interisland fares since then appear to be boosting travel by local residents, many of whom had cut back on Neighbor Island trips when one-way prices jumped to $80 or more after Sept. 11.

The new offer, at all three airlines, is good for travel through Dec. 31, except on Christmas, Thanksgiving, New Year's Eve and surrounding dates. Tickets must be purchased by Saturday.

Certain restrictions apply to the $29 fares, and the three airlines would not say how many tickets they will sell at that price.

Go! first offered $29 fares on July 29 and again on Aug. 8. Those fares were also matched by Aloha and Hawaiian.

Kailua resident Sabino Manzulli figured he saved about $400 when his family of four flew to Kaua'i on go! in June for $39 plus fees for each one-way ticket.

He said he used to travel with his family to Maui and the Big Island to visit friends several times a year but cut back to about once a year as prices soared. "It wasn't possible to fly a family of four until they (go!) came in."

Jonathan Ornstein, chief executive officer of Mesa, said yesterday: "I feel we've really made a positive change in Hawai'i. I continue to be delighted by the response from our passengers."

When go! started operating in June, it offered $39 one-way tickets, prompting Hawaiian and Aloha to match the fare.

Go! later sold a limited number of tickets for $19. Hawaiian matched the fare while Aloha gave 1,000 free roundtrip tickets to customers who lined up to get them.

The fare war comes as the state's two dominant carriers have emerged from recent financial troubles. Hawaiian Airlines emerged from bankruptcy protection in June 2005 while Aloha exited bankruptcy reorganization in February.

Reach Rick Daysog at rdaysog@honoluluadvertiser.com.