While the Canada eTA does not need to be printed, travelers must bring the following papers to the airport in order to board an aircraft heading for Canada:
The passport that was used to apply for the eTA.
Boarding pass (electronic or paper copy on a digital device)
As the Canada eTA cannot be transferred between passports, it is essential to obtain both the eTA and entry into Canada with the same passport. Consequently, if the passport expires while the eTA is still valid, a new authorization must be obtained.
Furthermore, while applying for the Canada eTA with dual citizenship, foreigners must supply the information about the passport they will use when visiting Canada.
To fly to Canada, all foreigners who require an eTA must obtain authorization.