US investment group Berkshire Hathaway, the investment group owned by Warren Buffett, has written down its investment in USAir, following the airline's failure to secure agreement on cost cutting from its unions. Buffett owns 13% of USAir and has seen the value of his holding slip from $385 million $90 million. British Airways has also warned that it may have to write down its 25% stake in the airline.

Source: Flight International