(Reuters) -Howmet Aerospace ( HWM ) will need to produce more parts this year for engines used in Boeing ( BA ) and Airbus narrowbody jets, as the planemakers ramp up output and the need for spares grows, the parts supplier's CEO John Plant said on Friday.

Plant's comments come a day after Boeing ( BA ) expressed optimism about increasing the production of the best-selling 737 MAX jets to 42 a month. The move could benefit players such as Howmet, one of Boeing's ( BA ) biggest suppliers.

However, supply chain challenges continue to weigh on the industry as Boeing ( BA ) and Airbus manufacture more jets, with no one particular bottleneck to blame.

Howmet also expects demand for its fasteners to rise, with global inventory running low after a fire at an SPS Technologies factory in Pennsylvania in February destroyed an important source of capacity.

"There's lots more to bid and we've got three customers already where we have production orders for as soon as we can make them," Plant said at a Bernstein conference.

He also acknowledged a force majeure letter on tariffs sent to customers in April, which was first reported by Reuters.

Plant said the letter helped get new agreements in place to cover exposure risk in case of an emergency.