United Airlines mechanics have unanimously voted Tuesday to turn down the contract offered by the air transport company. They then authorized a strike which brought to question the repair of thorny labor relations prior to the return of its company CEO.

More than 93 percent of the votes casted by the airline employees were opposed to the terms of the contract. The agreement is supposed to cover 9,000 mechanics involved in the bargaining group and more than 7,800 of them voted said the union.

"At a time when United Airlines is incredibly profitable, it is clear that mechanics deserve a better offer from the company," said Jim Hoffa, general president of Teamsters in a statement.

The union stated that the mechanics deserved to be treated better since the airline is earning good income. A recent report from United Continental Holdings showed that the Chicago-based airline company has made a $7.3 billion profit last year.

After the negotiation fell, the Teamsters union said they will request the National Mediation Board for permission to strike.

But before the board can grant their request, there must first be a declaration of impasse in negotiations. If not, the strike will be considered illegal. There will also be a 30-day 'cooling off' period before the airline mechanics could go on strike. Strikes in airline companies have been rare in the United States.

United Airlines CEO Oscar Munoz said in a statement that the company was disappointed with the result of the vote but was very eager to resume talks with the mechanics. He promised that he would personally meet with the union leaders to strike an agreement. Munoz was still recovering from a heart attack he suffered just six weeks after taking up his CEO post in United Airlines.

The company also said that the NMB has agreed to meet with them and the Teamsters union on March 3 in Washington for further talks.