Not necessarily. Here's an AC flight on Sept 21-Sept 28 Toronto to Orlando: taxes and fees work out to be $128 for the return flight
Passenger Type Adult
Departing Flight - Tango Plus 114.00
Returning Flight - Tango Plus 114.00
Surcharges 15.00
Taxes, Fees and Charges
Canada Airport Improvement Fee 25.00
U.S.A Transportation Tax 33.26
U.S Agriculture Fee 5.16
Air Travellers Security Charge (ATSC) 12.10
U.S Passenger Facility Charge 4.65
Canada Harmonized Sales Tax 3.25
Canada Goods and Services Tax (GST/HST #10009-2287 RT0001) 12.76
September 11 Security Fee 2.58
U.S.A Immigration User Fee 7.23
Number Of Passengers 1
Grand Total - Canadian dollars $348.99
The only thing that should vary here is the gst/hst since it is a percentage of the flight price. That's why Sunwing's crazy high taxes/fees really annoy me.