Hawaiian Airlines won a major round in its legal battle against Mesa Air Group, the parent of go! airline, when a federal judge dismissed the Phoenix-based carrier's antitrust suit against Hawaiian.

In a hearing yesterday, U.S. Bankruptcy Judge Robert Faris rejected Mesa's suit against Hawaiian, which alleged that Hawaiian was attempting to illegally block competition.

Faris also set Sept. 25, 2007, as the trial date for a suit Hawaiian's filed against Mesa. Hawaiian's suit charges that Mesa improperly used confidential information during Hawaiian's bankruptcy proceedings to prepare for the launch go!, which competes with Hawaiian and Aloha Airlines on interisland routes.

Mesa was one of several companies that looked at investing in Hawaiian to help it emerge from bankruptcy.

"Now that the court has thrown out the last of their (Mesa's) counterclaims, we're anxious to move forward with our case against Mesa and the substantial damage they are causing," said Mark Dunkerley, Hawaiian's president and chief executive officer.

"Mesa's arguments were never more than an attempt to distract our suit against them and from their predatory behavior."

Jonathan Ornstein, Mesa's chief executive officer, said he's confident that his company will prevail in the courtroom.

He said Hawaiian's suit and a related suit by Aloha are attempts to eliminate competition. If Hawaiian and Aloha succeed in their lawsuits, fares will double to where they were before go! entered the market, Ornstein said.

"They're trying to do to us in the courtroom what they can't do in the marketplace," Ornstein said.

Mesa triggered an interisland fare war when it launched go! on June 9 and began selling one-way tickets at $39. Go! later dropped one-way fares to as low as $19 during special promotions.

The discounts were matched by Hawaiian and Aloha and helped boost travel by local residents. Many local residents had cut back on Neighbor Island trips when one-way prices jumped to $80 or more after Sept. 11.

Hawaiian sued Mesa in federal bankruptcy court in February.

Hawaiian's suit asked the bankruptcy court for an injunction barring Mesa from flying in the interisland market for a year, but Faris denied the injunction.

During the hearings on the injunction, Hawaiian produced an e-mail by Mesa's chief financial officer, Peter Murnane, in which Murnane discussed giving Aloha, which was in bankruptcy last year, a final push to drive it out of business.

Mesa countersued Hawaiian in March. Faris dismissed all but one of Mesa's counterclaims earlier and yesterday rejected the final claim against Hawaiian.

In October, Aloha sued Mesa in state Circuit Court, alleging that Mesa is selling tickets below cost to hurt Aloha. The suit is pending.

Reach Rick Daysog at rdaysog@honoluluadvertiser.com.