Island Air, which in June slipped into third place among interisland carriers with a 3 percent market share, is focusing on improving its operational performance.

Hawaiian Airlines, with 92 percent, and Mokulele Airlines, with 4 percent, have the top two market shares among interisland carriers, according to the most recent data from the state Department of Transportation.

As part of its effort to boost performance, Island Air plans to release its on-time performance and flight completion data for each month and each quarter even though it is not required to do so.

The numbers will provide customers with a clear picture of Island Air’s “dramatically improving operational performance and the increasing quality of its service” on all of its interisland flights, the company said in a statement to be released today.

Island Air said 83.3 percent of its scheduled flights arrived on time in September to finish the third quarter with a punctuality mark of 80.4 percent.

A flight is counted as “on time” if it arrives within 14 minutes of its scheduled arrival time, according to the U.S. Department of Transportation.

The small local carrier said it also plans to have its monthly and quarterly operational performance numbers validated by a third-party industry expert to ensure the accuracy of its data.

The airline is not required by the U.S. DOT to report its operational performance. Only airlines that account for at least 1 percent of U.S. industrywide domestic scheduled passenger revenue are reflected in the DOT’s monthly Air Travel Consumer Report.

Island Air also said it completed 98.7 percent of all scheduled flights in September with nine cancellations out of 699 flights. For the third quarter, Island Air achieved a 99.2 percent completion factor with 17 cancellations out of 2,136 scheduled flights.

“While it has taken us over a year to achieve performance which is now very close to that of much larger airlines, we couldn’t be more pleased with how well our team has been doing, improving customer service and ensuring our passengers get to their destinations on time,” Island Air CEO Dave Pflieger said in a statement. “It is an honor and a privilege to work with such outstanding professionals as we continue to make ever-increasing improvements to our airline’s overall operations and customer service performance.”

Island Air, which is marking its 35th anniversary this year, flies 64-seat ATR-72 aircraft and serves Oahu, Maui and Lanai with more than 165 flights a week.