Canadian carrier WestJet has opted for the Bombardier Q400 as the type for its new regional carrier, to be set up in the second half of 2013.
WestJet has tentatively agreed to take 20 Q400s with options on another 25.
Bombardier, competing on its home territory for the deal, had been up against rival ATR whose runaway success over the past few months has left the Canadian airframer with only a handful of Q400 sales.
But Bombardier says the WestJet agreement - currently a letter of intent - marks a "proud day" for the manufacturer.
Up to 45 Q400s will be delivered to the airline over the next six years.
WestJet chief Gregg Saretsky says the carrier is "very impressed" with the Q400, and points out that both Bombardier and ATR submitted "excellent proposals".
But he states that the Q400's range, speed and seating density met the airline's requirements for its new regional operation.