CHICAGO — Mechanics at United Airlines soundly rejected a new contract and voted to authorize a strike.

The airline’s CEO said United was eager to restart negotiations and he would intervene to help reach an agreement.

The Teamsters union said Tuesday that more than 93 per cent of mechanics who voted turned down the company’s latest contract offer, which included a lower pay scale for new hires. United, the nation’s third-biggest airline, has more than 9,000 mechanics.

The Teamsters union said that mechanics deserved a better offer because the airline is very profitable — parent United Continental Holdings Inc. recently reported a $7.3 billion profit in 2015.

The union said it will ask the National Mediation Board for permission to strike.

Strikes have become rare in the U.S. airline industry. Under federal law, the board must declare an impasse in negotiations before airline unions can legally strike after a 30-day “cooling-off” period.

In a statement, United CEO Oscar Munoz said the airline was disappointed by the vote and was eager to resume bargaining. He vowed to meet personally with labour leaders to reach an agreement.

Chicago-based United said the mediation board has indicated it will meet with both sides March 3 in Washington.

Separately, United announced Tuesday that it reached tentative agreement on a contract extension through 2021 with about 420 dispatchers, who help pilots plan flights.