As background: the Quebec government bought $1B worth of the 'C Series program' (in terms of share value, who knows what that means, and it's a murky thing), which is the primary source of concern I believe.

Of course one could argue Boeing receives massive 'subsidies' from the US government in terms of pork-laden defence spending contracts. And other things, like incentives for various factories etc..

Airbus receives massive benefits from their network of R&D centres affiliated with Universities.

It's almost a farce to talk about aircraft manufacture as 'purely free trade' - its de-facto a partly nationalized industry everywhere.

There would be 0 large planes in the sky if governments were not involved.