Qatar Airways has let a deal for 50 Boeing 737MAX10 jets ‘expire’, courts documents submitted on Thursday at London’s High Court revealed.

The revelation that Qatar Airways has seemingly abandoned the $20 billion deal (at list value) came about as part of a pre-trial hearing into a multi-billion dollar lawsuit that the airline has brought against European aircraft manufacturer Airbus.

The deal has been allowed to expire just four months after being signed. It formed part of a larger agreement between Qatar Airways and Boeing signed in in April for 50 Boeing 777X freighter aircraft and two additional freighter versions of Boeing’s current 777 model.

The separate Memorandum of Understanding for the 737MAX aircraft was signed at a lavish event at the White House and was seen as a response to a decision by Airbus to unilaterally cancel Qatar’s order for its rival single-aisle aircraft – the A321neo.

Airbus cancelled the order for 50 A321neos because Qatar Airways has refused to take delivery of new A350 widebody jets in a dispute over a serious paint defect. A High Court judge has already ruled that Airbus was within its right to cancel the order and that leaves the Qatari flag carrier with a gaping hole in its future fleet plans.

Although the 737MAX10 isn’t an exact match against the A321neo, it is the best available from Boeing and no other aircraft manufacturer produces anything nearly similar.

But it now seems that Qatar Airways isn’t going to commit to the 737MAX10.

According to Reuters, Airbus requested a copy of the deal between Qatar Airways and Boeing for the 737MAX as part of its lawsuit preparation but Qatar Airways denied to request saying the deal had “expired”.

Qatar Airways has so far declined to comment on the matter, although the memorandum of understanding never committed the airline to buying the aircraft. Boeing does not discuss private negotiations with airline customers.

What Qatar Airways plans to do now in order to update its single-aisle aircraft fleet, remains to be seen.