First of all, I'm not sure if Air Canada was that much in need of national support as they claim. There were, perhaps, other airlines that were, but Air Canada went into this crisis, this pandemic, in a very good, strong financial position.
In terms of support, money should go primarily to restructuring for improving service and making services better, for better technology, for expenses that make the industry as a whole more competitive, and not just padding the executives' pockets or the corporation's coffers.
Also, money spent on preserving the skills of aviation workers and ensuring that they keep up with their training and their skills is definitely a good public money investment, because while the corporations and the shareholders are dispensable, the aviation workers are not. They are a national asset.