As a consequence of weight and engine problems, the A400M is €5bn ($7.25bn) over its initial budget.
Belgium, the UK, France, Germany, Luxembourg, Spain and Turkey have ordered 180 A400M aircraft in total between them and have been involved in long-run negotiations in recent months over how to share any additional funding between client states and the European manufacturer.
Further technical deals of the contract are expected later this week.
The A400M is designed to transport troops and equipment, and is expected to replace aging military cargo carriers in several European air forces.
The military plane, originally scheduled to enter service in 2009, will not take its maiden flight until 2012.