Washington: Air Transport Services Group Inc., a cargo carrier whose biggest customer is Deutsche Post AG's DHL, said 23 planes will stop flying for the German company in the next six months.

DHL will release the jets starting Monday under a plan to shift its US air-freight business to United Parcel Service Inc., Air Transport said yesterday in a statement. Wilmington, Ohio-based Air Transport's ABX Air unit flies the aircraft.

The announcement showed how DHL's transition to UPS will start to affect Air Transport's operations.

Bonn-based Deutsche Post said May 28 it plans to remove 39 of the 55 Boeing Co. DC-9 jets on which ABX Air flies DHL freight.

"This is the only notification we have received to date from DHL," said Wayne Buckhout, a spoke-sman for Air Transport who works for CTC Inc.

"DHL originally said that 39-aircraft phase could extend out 18 months, and this is over six months," he said.

Air Transport fell 4 cents, or 3.8 per cent, to $1.02 at 4 pm New York time in Nasdaq Stock Market composite trading on Friday.

The shares have plummeted 76 per cent this year, including a 42 per cent plunge the day of Deutsche Post's announcement.