Image caption Continental spurned a merger with United two years ago

United Airlines and Continental Airlines have been cleared to merge, creating the world's largest carrier.

Shareholders in the two airlines overwhelmingly voted to approve the deal on Friday.

The merged airline will be known as United Airlines, with Continental's chief executive Jeff Smisek taking on the same role at the new carrier.

Global airlines have struggled due to overcapacity, and United was forced into bankruptcy protection.

United and Continental announced their merger proposal in May, two years after Continental spurned similar advances from United.

The merger plan already has antitrust clearance from the US and European Commission.

"In approving the transaction, our stockholders recognised the value of bringing together Continental and United to create a platform for increased profitability and sustainable long-term value," Mr Smisek said in a statement.

Many carriers have struggled in recent years due to terrorist threats, soaring fuel prices and economic recession.

Several airlines have sought safety through merging. British Airways plans deals with Spain's Iberia and American Airlines.