Airbus SAS is close to sealing a purchase agreement from Kuwait Airways Co. for 25 aircraft in a deal valued at $4.4 billion based on list price, according to two people familiar with the matter.

The state-owned airline may sign the agreement as early as this month to purchase 10 Airbus A350-900s and 15 single-aisle A320neos, with deliveries starting in 2019, said the people, who asked not to be identified because the decision hasn’t been finalized.

Airbus won 616 orders by the end of April for the A350 series, which begins service before the end of 2014 and is designed to challenge Boeing Co.’s 787 and 777 widebody models. Boeing has begun marketing a successor to its 777, the 777X, though it hasn’t yet sought board approval to build the plane.