The appeal was dismissed. Interjurisdictional immunity was held to apply in the matter, under a two-part test that was stated by
McLachlin CJ: While ARPALAA is valid provincial legislation, it is inapplicable to the extent that it impacts the federal power over aeronautics. The federal aeronautics jurisdiction encompasses not only the regulation of the operation of aircraft and airports, but also the power to determine the location of airports and aerodromes. This power is an essential and indivisible part of aeronautics and, as such, lies within the protected core of the federal aeronautics power. In prohibiting the building of aerodromes on designated agricultural land unless prior authorization has been obtained from the Commission, the ARPALAA effectively removed the total area of the designated agricultural regions from the territory that Parliament may designate for aeronautical uses. This is not an insignificant amount of land, and much of it is strategically located. • Although s. 26 does not sterilize Parliament’s power to legislate on aeronautics the doctrine of paramountcy would permit Parliament to legislatively override provincial zoning legislation for the purpose of establishing aerodromes , it nevertheless seriously affected the manner in which the power can be exercised. • If s. 26 applied, it would force the federal Parliament to choose between accepting that the province can forbid the placement of aerodromes on the one hand, or specifically legislating to override the provincial law on the other hand. This would seriously impair the federal power over aviation, effectively forcing the federal Parliament to adopt a different and more burdensome scheme for establishing aerodromes than it has in fact chosen to do. In the appeal, it had been argued by Quebec that interjurisdictional immunity did not apply where a law raises a
double aspect. Although it was not necessary to decide that question, it was stated that the argument misapprehended the doctrine of interjurisdictional immunity: The doctrine of federal paramountcy would not apply in this case. • Paramountcy may flow either from the impossibility of complying with both federal and provincial laws or from the frustration of a federal purpose. Here, there was no operational conflict, since the federal legislation did not require the construction of an aerodrome and it is possible to comply with both the provincial and federal legislation by demolishing the aerodrome. • There was also no evidence establishing that a federal purpose regarding the location of aerodromes was frustrated by the provincial legislation. The federal regulations provide that the Minister responsible may determine that the location of each registered aerodrome is in the public interest, but they do not disclose any federal purpose with respect to the location of aerodromes.
Dissent Deschamps J declared that the only difference between the present case and
Quebec (Attorney General) v. Lacombe (which was released on the same day) was that
Lacombe was concerned with municipal zoning and
COPA with a provincial agricultural zoning scheme. She concluded that there was no evidence of an incidental effect that would amount to an impairment of the core of the federal aeronautics power. ==Impact==