Air Canada and Bombardier have finalized the details of a previously announced plan for the airline's purchase of 45 CSeries jets for an undisclosed sum.

At list prices, the jets cost as much as $3.8 billion US, but typically for a deal this size, the buyer would get a discount on the list prices. The two Montreal-based companies didn't specify an actual price tag in a news release announcing the deal on Tuesday.

The deal is for the larger of two models of CSeries and under the terms, Bombardier will deliver the first of 45 planes to Air Canada in 2019. The deal also includes an option for Air Canada to buy up to 30 more.

The companies announced a preliminary agreement in February as part of a series of initiatives by Bombardier, Air Canada, and the Quebec and federal governments.

The province agreed last week to provide the first $500-million instalment of a $1-billion investment in the CSeries program by the end of this month and the second instalment on Sept. 1.

Finance Minister Bill Morneau said Ottawa is still negotiating potential financial support for Bombardier, which is seeking $1 billion from the federal government.