Lots of history on this. Some of the taxes are actually refundable, such as $5.60 TSA tax and immigration, customs, and APHIS fees on international tickets. As for the other taxes , the IRS has ruled that the 7.5% US domestic excise tax, the $4.10 US segment tax, and passenger facility charges are not refundable on non-refundable fares. Good luck fighting with the IRS.
"By law, this tax applies to the sale of air transportation, not to the transportation itself. Airlines remit this tax to the government shortly after the ticket is issued. If the passenger changes his or her schedule and forfeits the air fare on a non-refundable ticket, the airline still owes this tax to the government."
https://www.elliott.org/blog/surpris...dable-tickets/
You can see the refundable taxes listed on Air Canada's website. Click the "Are taxes, fees and additional charges associated with my ticket refundable?" link --
https://www.aircanada.com/us/en/aco/...-services.html
Okay I don't like it, but I understand. So are the "facilities" fees (as opposed to TSA fee) also considered a "tax" and therefore non refundable?