Planemakers are looking at drastic cuts in wide-body production amid a slump in demand for the industry's largest jetliners, manufacturing and supplier sources said on Thursday.

Deliveries of long-range jets like the Boeing 777 or 787 and Airbus A350 or A330 have been particularly badly hit as airlines seek deferrals and many withhold progress payments.

"At a minimum, the (Boeing) rate could fall by at least half," one industry source said, speaking on condition of anonymity.

Airbus also faces likely cuts in wide-body jet production, but no decision has been taken, the sources said.

Both planemakers declined comment.