US, April 24 -- When Air Canada took delivery of its first Airbus A321XLR this month, the moment was framed publicly as a routine fleet upgrade - another step in modernizing aircraft and improving efficiency.

But within the aviation industry, the delivery is being read as something more: part of a quiet but notable shift among Canadian airlines toward European manufacturer Airbus, and away - at least incrementally - from its longtime American rival, Boeing.

The new aircraft, one of 30 A321XLRs Air Canada has on order, is designed to fly farther than traditional narrowbody jets while consuming significantly less fuel. It allows the airline to connect cities like Montreal and Toronto directly to smaller European destinations - Berlin, Tou...