We have estimates based on financial data published by those airlines that are publicly traded, and as such, they have public financial reports. Air Canada currently holds about $2.3 billion in advance ticket sales. Projecting that to the entire Canadian airline sector, we estimate that about $3.87 billion is outstanding. A very conservative estimate would mean that corresponds to about 3,870,000 passengers who are affected.
The exact numbers are available only to the airlines themselves. They should be producing that data to the committee.