In a 18-page complaint filed in state Circuit Court, Aloha said that Mesa received proprietary information when Aloha was in bankruptcy and improperly used the information to launch go! on June 9.

The suit, echoing a lawsuit against Mesa by Hawaiian Airlines, alleged that Mesa is selling tickets below cost to hurt Aloha. The Aloha lawsuit cited a September e-mail in which Mesa's Chief Financial Officer George Murnane stated: "We definitely don't want to wait for them (Aloha) to die; rather we should be the ones to give them the last push."

Aloha, which emerged from bankruptcy in February, asked for a preliminary and a permanent injunction barring Mesa from selling tickets below cost as well as monetary damages.

Mesa spokesman Paul Skellon had no immediate comment, saying the company has not yet seen the suit. In response to Hawaiian's lawsuit, Mesa officials said the e-mail was taken out of context and they did not use information gained during Aloha's bankruptcy to help them compete against Aloha.