BAA: No margin for error
The 10% fall in passenger numbers going through Heathrow, Gatwick and Stansted during the first three months of this year is one of those numbers - like the halving of Japanese exports - that shouts about the depth of the recession.
That sort of plunge in numbers flying has happened before for BAA. There was a 9.9% drop in passenger traffic during the three months that followed the September 11 terrorist outrages.
But the plunge in 2001 was fairly short-lived. By contrast, this year's fall follows a 7.1% dip in passengers for the previous three months.
That said, BAA hopes - and believes - that it's over the worst.
Its optimism is based on its analysis that the underlying passenger decline between January and March was "just" 7.2%, adjusting for the impact of a later Easter and a colder winter.
BAA, which is owned by the Spanish group Ferrovial, also draws attention to the smaller fall at Heathrow (which it estimates at less than 4% in underlying terms), than at Gatwick and Stansted - since Gatwick and Stansted are being sold on the orders of the Competition Commission.
The debt-encumbered business rather needs this "glass-half-full" analysis to be true, since it only just hit the forecast it made last October for EBITDA, or earnings before interest, tax, depreciation and amortisation (the most common proxy for cash flow).
In its supplementary prospectus dated October 1, BAA forecast that adjusted EBITDA for the whole year to March 31 (not just the three months) would be no more than 5% below £1,015m, or at least £964m. In the event, adjusted EBITDA was £968m.
If earnings had been less than half of a percentage point lower, it would have missed the target. That half percent has no statistical significance but means the world in psychological terms.
How did it scrape by?
Well, it squeezed costs. And thanks to a regulator that allowed BAA to levy increased charges on airlines for using Heathrow and Gatwick, what BBA calls "aeronautical income" rose almost a third.
Ain't it great having a de facto monopoly?
Also, the smaller numbers who flew forgot there's a recession and splurged a good deal more: there was a small increase in BAA's retail income.
But for me, the most interesting part of BAA's results announcement is a phrase that the company has highlighted in bold (presumably so that its creditors don't miss it).
In flagging up a review by the Department for Transport of how it's regulated, the airports group says it expects to be subject to a new licensing regime that would impose a "new duty on the regulator to ensure that licence holders can finance their activities".
So it would risk losing its licence to operate Heathrow if it was perceived to be too financially stretched.
The point is that BAA has an eyewatering £11.4bn of borrowings - or a hefty 11 times EBITDA - including just over £1bn that are classified as "current" (or repayable within a year").
In other words, BAA's tender parts are still in the vice-like grip of its lenders.
Still, it had a miraculous escape from bankruptcy last year: some £9.1bn of debt was due for repayment within a year, as of March 31 2008.
That, of course, necessitated the mother of all refinancings. It rather defies belief that BAA pulled off the refinancing, in the worst financial-market conditions within living memory.
But that doesn't mean it can relax. Although the recession means that its income is subject to the most painful squeeze in living memory, its lenders are unlikely to be especially tolerant or forgiving if BAA lets them down.
It matters, in that context, that in the next few weeks it achieves a decent price for Gatwick and that prospective purchasers aren't put off by the 14.6% fall in first-quarter passenger numbers - since the proceeds of that forced disposal will be used in their entirety to pay a portion off the "Refinancing Facility".
So BAA is unlikely to revert to being a dull, steady-as-she-goes utility any time soon.
And although it's understandable that for many business people and politicians the big question is whether Heathrow should be allowed a third runway, that looks almost an academic issue compared with BAA's operating and financial challenges.