Paris and Berlin have been sparring over the massive project for months as Dassault's CEO, Eric Trappier, pushes for a dominant role overseeing the building of the jet.

Here is an overview of the situation:

What is the project?

The Future Combat Air System (FCAS), a roughly 100 billion euro ($119 million) project, is more than just a fighter jet.

It's a complex interlinked air combat system that also includes drones and a digital data cloud communications system.

The first FCAS aircraft are supposed to be ready for service around 2040, although delays had raised some doubts about that timeline.

In the long term, the FCAS is supposed to replace Germany's Eurofighter Tycoons and France's Dassault Rafale jets.

Launched with fanfare in 2017 by French President Emmanuel Macron and then-German chancellor Angela Merkel, the project was joined two years later by Spain, led by Spanish defence contractor Indra Sistemas.

It has taken on particular importance as Europe scrambles to rearm in response to Russia's invasion of Ukraine -- and as European allies seek to demonstrate their ability to work closely together on defence.

What are the disagreements?

French and German political leaders promised to reach a compromise on FCAS by the end of 2025, or else decide to split up the programme.

But that deadline has been and gone, with no decision yet made public.

At the heart of Franco-German tensions are disputes over intellectual property rights, future export prospects and the share of work allocated to contractors in each country.

Under the existing agreements, France, Germany and Spain are each to contribute one-third to the development costs.

But Dassault, responsible for developing the aircraft itself in partnership with Airbus operations in Germany and Spain, is demanding contract changes to allow it the freedom to choose its subcontractors.

What is Berlin's stance?

At the end of January, German Chancellor Friedrich Merz acknowledged that there were "differing conceptions from our own" about the project.

Since then, several media outlets have reported about the project's imminent abandonment.

An article in the German weekly Stern said Merz informed his ministers in mid-January that there would likely no longer be a joint fighter jet.

The German government has officially denied that report. A spokesman told AFP that "no decision on the future of the FCAS project" had "yet been made".

French President Emmanuel Macron endorsed FCAS in an interview Tuesday with several European newspapers and demanded that "things must move forward".

"It's a good project, and I haven't heard a single word from the Germans suggesting it's not a good project," he said.

But Macron also issued a warning to Berlin with an allusion to another major Franco-German defence project to build a new battle tank that has long been informally linked to FCAS.

"If, by chance, the German partner were to question the joint aircraft programme, we would be forced to question the joint tank programme," Macron said.

Are there alternatives?

In Germany, aerospace industry figures and politicians are increasingly raising the possibility of developing separate fighter jets -- which might still share some FCAS systems.

Building two separate aircraft, however, would be more expensive.

Trappier, Dassault's brash and politically connected CEO, has boasted in interviews that his company could build the project alone.

But France's difficult budget situation leaves doubts about whether the French government could shoulder the costs alone.

For Germany, one possibility would be to partner with Sweden's Saab instead.

Another option could be joining the competing Global Combat Air Programme (GCAP), also known as Tempest, a joint effort between Japan, Italy and the United Kingdom.

But since that project is already well under way, it is unclear whether German contractors could carve out a significant role.

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Dassault Aviation

Airbus Group

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