American cancels 595 more flights

More than half of American's MD-80 fleet should be back in service

Thousands more passengers have endured disruption and cancelled flights as American Airlines continues to check its MD-80 aircraft for wiring problems.

In the fourth day of cancellations, American said it had to ground 595 flights on Friday, taking the total for the week to more than 3,000.

US airlines have been ordered to check the wiring on all MD-80 aircraft.

Alaska Airlines, Midwest Airlines and Delta Air Lines also had to cancel MD-80 planes on Thursday for checks.

American Airlines axed about 1,000 flights on Thursday and Wednesday, and 460 on Tuesday.

The US's biggest airline said customers could apply for a refund or use the value of their ticket towards another flight.

Customers scheduled to travel on any MD-80 flights until 13 April can switch onto any other available American flight as long as they travel before 17 April, the company said.

The MD-80 was made by former US plane firm McDonnell Douglas, which was bought by Boeing in 1997.