Germany's second-biggest airline, Air Berlin, has told Boeing it will no longer need its full order of 787 aircraft.

The airline said market conditions had changed its requirements.

Air Berlin has lowered the number of firm orders of 787 aircraft from 25 to 15 and has also reduced the number of options on 787 aircraft from 10 to 5.

The planes were originally scheduled for delivery in 2010 or 2011.

Many airlines have delayed or cancelled orders due to the slump in air travel, which has been on a downward trend since 2008.