Go! (styled as go!) was a regional brand of Arizona-based Mesa Airlines. Go! operated inter-island services within Hawaii. Its main base was Honolulu International Airport. It was a division within the Mesa Airlines subsidiary of Mesa Air Group and its flights were operated by Mesa Airlines. The airline ceased operations in Hawaii on April 1, 2014. The company slogan was Hawaii's Low Fare Airline. History Regional carrier Mesa Airlines started Go!'s inter-island operations on June 9, 2006, using five Bombardier CRJ-200 regional jet aircraft. In September 2006, the airline announced that it had reached an agreement with Mokulele Airlines, whereby Mokulele would operate Cessna Grand Caravan aircraft to Kapalua, Molokai, and Lanai under the name Go!Express. Service began with flights from Kapalua to Honolulu, Kahului, and Kona on April 17, 2007. Service began for flights to Molokai on July 21, 2007 and flights to Lanai on October 6, 2007. Following Mokulele's agreement with Republic Airways Holdings to have that company operate flights in Hawaii using 70-seat jets, Mesa announced that it would be terminating the Go!Express agreement with Mokulele in April 2009. The airline later accelerated plans to terminate the agreement with Mokulele, and ended the code-share on March 24, 2009, replacing it with a new agreement with Island Air that allowed Mesa to sell existing Island Air flights with the Go!Express name. On March 17, 2014, Mesa announced that Go! would cease service on April 1, 2014, with its aircraft re-deployed to support Mesa's operations on the U.S. mainland. The airline also stated that a long term increase in the cost of fuel had prevented the operation from being profitable. Lawsuits over formation In February 2006, before the airline had started flying, Hawaiian Airlines filed a complaint for injunctive relief. In its complaint, Hawaiian Airlines noted that Mesa Air Group had been a potential investor during Hawaiian's Chapter 11 bankruptcy proceedings and as such, had access to confidential business data that it alleged Mesa then used in developing Go!. Hawaiian claimed that the confidentiality agreement under which potential investors were given access to the data prohibited the use of that information to compete with Hawaiian for a period of two years. In a memo explaining his decision to rule against Hawaiian's request for a preliminary injunction, U.S. Bankruptcy Judge Robert Faris wrote that e-mail made public during Hawaiian Airlines lawsuit raised "real doubts about the propriety of Mesa's conduct."