Losses at go! widened during the first three months of the year as rising fuel costs continued to take their toll on the interisland carrier.

In a filing with the Securities and Exchange Commission yesterday, Phoenix-based Mesa Air Group said its go! subsidiary lost $8.3 million during the three months ending March 31, up from a loss of $3.9 million during the same period a year earlier.

"It's been a tough environment both financially and operationally," Mesa Chief Executive Officer Jonathan Ornstein said in a conference call with investors yesterday.

"I don't think I'm going too far out on a limb (to say) that if we entered the market and fuel prices were at the same level, go! would be significantly profitable today. But unfortunately again we've seen fuel prices effectively double since that time two years ago and that has impacted us negatively."

The March 31 shutdown of Aloha Airlines had little impact on go!'s second quarter results, but likely will have a positive impact in the following quarter.

Even with Aloha's shutdown, which boosted go!'s passenger counts and load factors, the interisland carrier has struggled because of soaring fuel prices. Go! reported flying 87,577 passengers in May, a 51 percent increase from May 2007.

Mesa said go!'s operating expenses increased by more than 64 percent to $15.5 million because of higher fuel prices. Revenues, meanwhile, jumped nearly 29 percent to about $7.2 million during the second quarter because of higher interisland fares.

In January, go! increased its standard interisland fare by $10 each way to $49. go! matched a $5 fare increase in April by Hawaiian Airlines, raising its basic fare to $54. The following month, go! again matched Hawaiian in raising fares by $10 to $64.

The string of fare increases comes after Hawaiian, go! and now defunct Aloha were locked in a costly, 18-month fare war set off by go!'s June 2006 startup.

Since its 2006 launch, go! has lost more than $30 million in Hawai'i.

Go!'s latest results come as parent Mesa reported second quarter earnings of $9.4 million, or 29 cents per share.

Mesa's profit compares with a loss of 75 cent per share, or $23.9 million loss, during the year-earlier quarter.

Shares of Phoenix-based Mesa rose 6 cents yesterday to close at 51 cents on the Nasdaq Stock Market.

Mesa said it resolved a number of legal issues during the quarter.

In April, Mesa settled a lawsuit by Hawaiian Airlines by agreeing to pay Hawaiian $52.5 million. A federal judge earlier ordered Mesa to pay Hawaiian $80 million plus legal fees for misusing confidential business information.

In May, a federal judge in Atlanta issued a preliminary injunction against Delta Air Lines prohibiting Delta from canceling Mesa's $20-million-a-month contract to provide regional service for Delta.