Excess capacity created by Mesa Air Group’s Go! unit has forced Hawaii’s largest turboprop island hopper, Island Air, to ground its Bombardier Q400 only five months after receiving it from the manufacturer. Island Air has also postponed delivery of two more Q400s for at least six months while CEO Rob Mauraucher looks for a place to temporarily redeploy the first airplane. “It is clear that Go!’s recent $19 fare was a direct attempt to damage yield throughout the marketplace and a blatant effort to drive an airline out of business,” said Island Air in a statement.  “Island Air is therefore proactively taking prudent defensive measures to ensure we can maintain our position in the marketplace.” The airline emphasized that the equipment decision will not affect routes or schedules, now served exclusively by de Havilland Canada Dash 8-100s.