Boeing said it would have to redesign parts of its 787 Dreamliner, raising the prospect of a new delay to the new aircraft, the Financial Times reported on Thursday.

According to the FT, Boeing was responding to a warning from the chairman of International Lease Finance, the 787's biggest customer, saying the state of the 787 program was "not pretty".

Boeing told the FT it is doing some redesign work but said the ILFC was not painting an accurate picture of the overall program.