United Airlines is looking at outsourcing neighbor island ground operations, which could result in the layoff of 223 employees at the Kona, Kahului and Lihue airports.

The airline, which has more flights to the state than any other carrier, last week notified workers at those three airports, as well as 12 small mainland airports, that it is looking at competitive market rates to see whether ground operations work can be kept within United. The airline said it currently pays the same labor rates in all markets, unlike its major competitors, whose rates at smaller airports are in line with local market rates.

"This difference in pay puts us at a competitive disadvantage, and we must look for ways to ensure our cost structure is more in line with other airlines serving the markets," United spokesman Christen David said Thursday. "We haven’t made any decisions, but we must continually look for new opportunities to run a more efficient and financially sustainable business."

The International Association of Machinists & Aerospace Workers Local 141, which covers the affected Hawaii employees, said in a bulletin that United contracts include language that prevents United from making the unilateral decision to outsource work without first entering into negotiations with the union over every airport considered.

"Negotiations will begin as soon as possible and deal with each station (airport) separately," the union said. "Discussions will be based on what the (Requests for Proposals) has shown as a potential cost, and what, if any, adjustments can be made to current contract provisions to keep IAM members in their locations."

The union said it understands that United has received responses from multiple vendors to perform the outsourced work for the affected airports. The potential layoffs do not involve pilots and flight attendants.

United is scheduled to bring 826 flights and 184,166 air seats into Hawaii this month from the mainland.