Ryanair chief executive Michael O'Leary yesterday criticised the "flight-shaming" movement promoted by Greta Thunberg and other climate campaigners.
He said they are peddling a "fallacy" that air travel could be replaced by other modes of transport.
Mr O'Leary said efforts by campaigners to reduce air travel have so far had no impact on reducing airlines' carbon footprint.
"I don't pay too much attention to them," the Irish executive said. "There is very little evidence of the impact of flight-shaming or Greta Thunberg."
The comments came as Ryanair posted record half-year profits of £1.22billion, higher than the £1.04billion posted in 2019 - the last relevant comparator given the impact of the pandemic. The results were broadly in line with investor expectations.
The aviation sector's emissions are under the microscope at the UN's COP27 climate-change summit in Egypt this week.
Emissions
The global aviation industry emits around 2% of all human-made CO2 emissions, according to industry figures.
However, the Telegraph reports that Mr O'Leary said the idea of the public using alternative modes of transport to replace air travel was impractical.
"We live on an island in Ireland and the UK," he said. "The idea that we can all simply go by train on weekends when there aren't train strikes is a fallacy."
He added that road transport is responsible for 27% of Europe's CO2 emissions.
"Now nobody believes we can eliminate road transport. But equally if you live on an island or on the periphery of Europe, you can't eliminate air travel either."
Ryanair said yesterday that it intends to invest in the production of sustainable aviation fuel (SAF), which is made from a variety of products including used cooking oils, household waste and used clothes.
Mr O'Leary said: "We have to look at every way of improving or reducing the fuel consumption of air travel."
- UK Prime Minister Rishi Sunak has told COP27 that the war in Ukraine is a reason to act faster to tackle climate change. He said:"Climate and energy security go hand-in-hand."