The United States wants to resolve the long-running trade conflict between aviation giants Boeing and Airbus by July, US Trade Representative Katherine Tai told a congressional panel Wednesday.

US President Joe Biden and EU leader Ursula von der Leyen had in March suspended retaliatory tariffs in the 16-year-old transatlantic dispute over subsidies for the rival planemakers, and Tai told a Senate committee the sides intend to reach an agreement by the summer.

"I have made clear that we are interested in resolving these disputes in this four-month period, and I would very much like for us to make the kind of progress between now and July," Tai said.

Asked if the Biden administration would extend the pause without an accord, Tai said the administration was "very serious" about ending the feud.

US Trade Representative Katherine Tai testifies before the Senate Finance Committee on May 12, 2021 in Washington
US Trade Representative Katherine Tai testifies before the Senate Finance Committee on May 12, 2021 in Washington GETTY IMAGES NORTH AMERICA / POOL

"We really need to have these disputes resolved," Tai said.

Each side has won rulings in the dispute before the WTO, which authorized the governments to impose punitive tariffs. The two sides have levied duties on each other's plane manufacturers, while Washington has put tariffs on a record $7.5 billion in EU goods.

These target European products like wine, cheese and olive oil, while the EU had placed duties on American farm products such as wheat and tobacco, plus alcoholic spirits and chocolate.

Among other matters raised during the hearing, Tai said "very critical issue areas are still open" in talks between the United States and Britain towards signing a trade accord.

Tai said these include "the situation in Northern Ireland" following Britain's departure from the European Union.