Earlier this month a WTO dispute panel found the US had dealt with all but one of the instances of illegal subsidies to the aerospace giant.
But Airbus maintains the US continues to offer unfair support.
The fight is part of a 13-year dispute between the EU and the US over support offered to Boeing and Europe's Airbus.
In 2012, the WTO found that state and federal programmes provided Boeing with billions of dollars in illegal subsidies.
On 9 June the WTO's dispute panel found most of those issues had been addressed.
However, generous tax benefits offered by the state of Washington, where Boeing has a large presence and which are worth an estimated $800m to date, continue.
Both sides claimed the panel's June findings as a victory.
The WTO has also found that Europe provided billions in illegal subsidies to Airbus.
The European Union (EU) has appealed against a recent World Trade Organization (WTO) ruling in favour of the US over its state aid for Boeing.