A few speakers rely heavily on their data slides which I'll try to update when they're released over the next week or so. One of those is Nikolas Hill, a senior consultant with AEA, but he is also the one speaker to speculate - in response to a question - about where the UK Conservatives got their figures. Notably the one that says high-speed rail is 70X cleaner than air travel.

One of the day's most interesting speakers is not actually on the agenda, but Michel Leboeuf of the Systra consultancy arm of French rail operator SNCF gets plenty of attention when he speaks from the floor.

Michael Hayes, managing consultant for Atkins Transport Planning, puts out the question: "Is Heathrow important to the business case for high-speed rail?" And he continues: "If you are going to build this very expensive piece of kit, which markets do you want to serve?"

He points out the complexities of trying to serve the markets for Birmingham and also for Liverpool further north, and he suggests that only Scottish traffic would experience a "significant" shift from air to rail. It might lead, he suggests, to a solution with better conventional long-distance rail services with "occasional" high-speed trains on the longer routes.

"This comes across as saying there is not case for high-speed rail," he frets. "I think there is a case, but it has got to be part of a bigger solution."

Prof Robert Cochrane of Imperial College London, who was heavily involved in the the landmark Eddington study of UK transportation, also bemoans the inadequate data - particularly on non-aviation travel, and especially the roads.

Next up is Stuart Condie, BAA planning services director and the man whose show it is.

I'm just back from a small but perfectly formed conference in London organised by BAA and designed to help them, and anyone else, understand how Heathrow and the national rail system should be linked - or not. With particular emphasis on the case for high-speed rail. BAA plans to come out with its own proposals in summer 2009.

All of a sudden this has become a big deal after the UK opposition Conservative party announced, to the astonishment of just about everyone, that they would not go ahead with building the third Heathrow runway and would instead invest in high-speed rail. Their leader David Cameron personally put his name to this idea. As the Conservatives have at least an evens chance of being the next government, this is not a trivial matter.

At the conference, where there are something like 100 attendees from business, academia, consultancies etc, there is general bafflement at what the Conservatives are doing and where they sourced their supporting data.

It's kicked off by chairman Tony Travers, director of the Greater London Group at the London School of Economics. Drily noting that Heathrow is "a national treasure" - a very British, and decidedly two-edged description - he says: "High speed rail could make Heathrow easier to access and greener but, and there is a paradox here, easier to expand."

Today and tomorrow the participants in Europe's Green Regional Aircraft (GRA) programme are in Caserta, Italy to get the technical activity underway. Briefly, GRA is one of the six strands of the all-important Clean Sky research programme. That in turn is the pan-European research effort aimed at helping industry achieve the continent's environmental targets in aviation. GRA accounts for €174 million of Clean Sky's €1.6 billion over seven years.

Well I suppose the headline above is pretty well guaranteed to spark the critics into action, but the Sustainable Aviation Fuel Users Group launched by Boeing, Honeywell, a group of ten airlines, and two environmental groups has had a remarkably neutral reception. In the tinderbox of the aviation environmental debate that's quite a success.

Another noteworthy feature of this project is that it was kept quiet until launch - also quite a feat in the leaky aviation world. The two points may not be unconnected. Obviously the new group now has to deliver, but in the short term it's difficult to argue with its aims, and opponents may just be drawing breath.

Meanwhile, I've scoured the blogosphere and just about nobody has a rude word to say about it - for now. This blog is from Liz Barratt-Brown at the Natural Resources Defense Counsel (NRDC) which is one of the partners in the group - but it's an interesting viewpoint all the same.

It's the annual conference of the Conservative Party in the UK. Regardless of how thrilling or otherwise you may find this, the fact is that they are very publicly committing to actions that stand an excellent choice of forming the manifesto of the next national government.

And a huge commitment they made today was to confirm beyond any doubt that they do not intend to go ahead with approving a third London Heathrow runway. That came from shadow transport secretary Theresa Villiers. Their leader David Cameron said as much before, and so did London's Conservative mayor Boris Johnson (although he has his own unique wrinkle on the argument). Now there's no going back.

They'll be spending the money on high-speed rail from major northern cities and London instead.

The declaration has had predictably but decidedly mixed receptions as reported here in The Guardian and here by the BBC. This of course is not a debate that lends itself to neat conclusions - but the "false choice" between air and rail argument does seem relevant.

In the reasonably plausible event of the next election ending with a Conservative victory but a 'hung' parliament, the Tories could count on the Liberal Democrats for support on this issue.

Peter Bakker, who I've not met, is CEO of the integrated freight company TNT, and a very interesting man. He's close enough to aviation to know a great deal about it, but distant enough not to be too much in love with it. And he's just said something fairly remarkable.

TNT operates or controls more than 40 aircraft worldwide under the TNT Airways brand. Most of them are short/medium-haul frieghters for express deliveries. But the airline also has a couple of  Boeing 747-400ERFs for long-range services - notably Europe-China.

Business is good and the airline needs more long-haul aircraft, but Bakker says TNT has told Boeing he won't be acquiring more 747s.

My colleague Brendan Sobie talked to him at the Cargo Facts symposium in Miami about why - read below why Bakker thinks what he thinks.