PP member Guillermo Mariscal explained that he believes the initiative is “ineffective” because it would only result in a 0.06 per cent reduction in emissions according to data from the College of Aircraft Engineers (COIAE).
It says in the article, the number of flights this would affect might be very small. They originally wanted to ban flights with a train alternative under 4 hours, but that didn't get through.
Because he's from the college of aircraft engineers, who may have a vested interest in flight, and is therefore paid to make that number look as small as possible.
The article talks about a plan, which depending on what it includes would vary. In the article one optimistic prediction says 10% the other more pessimistic says 0.06%. Until more decisions are made the real number will be unknown.
It might be a low number, but then again this also seems like a initiative that will affect an even smaller number of people and is targeting something where a completely valid alternative exists, that has lower emissions.
It might not be the end it all solution, but there won't be one of those. So measuring it by that standard seems pointless to me.
I'd rather look at things like: Is there an alternative (and if so, what compromises does it make), what are the relative gains, and how easy is it to implement? And banning short distance flights seems to check those marks in my book.