Airlines have to radically change their operational models by phasing out short-haul flights where alternatives such as rail are available, according to Green MEP Ciaran Cuffe.
He said people need to rethink the requirement for business trips - and consumers may have to learn to live without weekend trips abroad.
"We need to move towards low carbon mobility," Mr Cuffe told a PwC webcast on sustainability yesterday. "We do have to rethink aviation.
"They [airlines] need to phase out short-haul flights where there's an alternative by rail.
"A green future will have a lot less flights - the end of the weekend break in Prague or Madrid. Yes, aviation will still be there, but there has to be less of it if we're to reach our carbon targets," he said.
"We're not going to be flying electric planes across the Atlantic any time soon. The lesson there is that we need to reduce the long-haul and short-haul aviation and look at other sectors where businesses can thrive."
Mr Cuffe's comments on the aviation sector may carry more weight than they might have previously, given that the Green Party is now in government and its leader, Eamon Ryan, is the minister for climate action, communication networks and transport.
A spokesman for the DAA, the semi-State firm that operates airports at Dublin and Cork, said air connectivity plays a "vital role" in the Irish economy and it will be critical now that the United Kingdom has left the European Union.
"Without flying, most business travel from Ireland - which underpins huge elements of the economy - would not be viable and holidays here from many of our major inbound tourism markets also require trips by air," the DAA spokesman said.
Dr Cara Augustenborg, an environmental policy fellow at University College Dublin, told the PwC webcast that the new Government should be looking at ways in which the country can achieve emissions targets.
She said no new "fossil fuel infrastructure", including airport runways or roads, should be built.
The DAA is constructing a €300m-plus runway at Dublin Airport. It was designed to help facilitate a surge in passenger traffic that the hub had experienced in recent years.
"Dublin Airport's new north runway, which is being funded by DAA and is being developed in line with Ireland's national aviation policy, will be crucial in helping the Irish economy to recover from the post Covid-19 recession and will create new employment, investment and export opportunities throughout the country," the DAA spokesman said.