In a statement, the environmental association considered that "this is a fair tax measure," since domestic flights "do not constitute a necessity like basic food items."

The proposal comes in connection with the discussion of the 2026 State Budget, with ZERO adding that applying a reduced rate to travel between Lisbon, Porto, Faro, and the islands of Madeira and the Azores "is an indirect form of tax subsidy for fossil fuels."

This measure, if applied, would allow the State to "collect additional revenue of at least €100 million per year," the environmental defense association pointed out, adding that the amount is "equivalent to the investment in approximately 1,000 housing units every year under the public housing scheme at controlled costs."

Domestic flights between Lisbon, Porto, and Faro are subject to a 6% VAT rate, while other flights between mainland Portugal and the Azores and Madeira islands are exempt from VAT.

"This situation violates the principles of social justice, since air transport is mainly used by higher-income segments, while families with fewer resources pay VAT at the same rate or a higher rate on basic products," the statement reads.

This proposal, the ZERO association also pointed out, does not affect residents and students of the autonomous regions, as they are covered by the social mobility subsidy, meaning that the amount paid for travel is fixed by law, regardless of the ticket price charged by the airline.