Airbus will take a majority stake in Bombardier's marquee C-Series airliner programme, the companies announced, as the Canadian firm battled against a stiff tariff ruling in the US.

The landmark agreement comes after the US administration slapped a 220 per cent countervailing duty, as well as an 80 percent anti-dumping tax, on Bombardier CS100 and CS300 aircraft imported into the US. Boeing accuses Bombardier of manufacturing its 100-150 seat planes with public subsidies and selling them at a loss to Delta Air Lines.

The agreement between Airbus and Bombardier aims to allow for significant production savings on the C-Series aircraft and to make use of Airbus's international reach for sales, the two groups said in a statement.

"It's a win-win deal for everyone," said the president of Airbus, Tom Enders.

Airbus will take approximately 50.01 percent of the shares in CSALP, the entity which manages the C-Series program, with Bombardier and Investissement Quebec holding 31 and 19 per cent respectively.

"We are very happy to welcome Airbus to the C-Series program," Bombardier's CEO Alain Bellemare said.

The C-Series is a state-of-the-art aircraft largely built from composite materials. It complements Airbus' medium-range carrier, the A320, which can carry some 140 passengers. Bombardier's C-Series is the first new design in the 100- to 150-seat category in more than 25 years, and US-based Delta Airlines has ordered 75 of them.

The US aerospace firm Boeing, claiming its competitor received unfair state subsidies, successfully petitioned the Trump administration to impose financial penalties on Bombardier to keep it from selling its C-Series planes in the massive US market.

In turn, Canada has voiced interest officially in some Australian military aircraft and called off discussions with Boeing on a possible purchase of 18 new Super Hornets. It intends to renew its fighter jets and is set to seek offers in 2019.