Maybe this is where this is coming from?
I re-call this case, where an Air Canada pilot that was resident in Bermuda (and another on a US border town) had to calculate flying time in Canada to figure out their Canadian taxes. Even on domestic flights (YVR-YYZ), less than half of the income was attributable to Canada. No idea if they had to file US tax returns for the time over US airspace.
There's a tax case with the code: 2011tcc449
There's a globe and mail article with the code article4255708/