One in particular.

Not the astonishingly large list of advisers for the deal . . .

though the ones I've met are smart and work hard. Not the employees . . . though they too are hardworking and the vast majority of whom act like people who appreciate that they stand to make a few bob off the deal.

Not current management . . .

though chief executive Dermot Mannion radiates Zen-like calm under pressure.

Not even former boss Willie Walsh, who saved Aer Lingus from post-9/11 bankruptcy five years ago and did most of the hard work transforming the business.

The real party they should thank is Ryanair, and Michael O'Leary in particular. His relentless pursuit of profit has made Ryanair Ireland's best-regarded company among business leaders around the world. But don't tell that to certain worthy observers in the Irish mediapolitical complex who sneer at the very mention of O'Leary's name.

This week O'Leary went even further down in their estimation . . . and up in my own . . . over his announcement this week that from next summer you will be able to use your mobile on a Ryanair flight.

O'Leary anticipated that his critics would react sharply, bemoaning "the decision to discard one of the world's last mobile-free havens" as the Irish Times put it after a grumpy litany of Ryanair's other sins against comfy inefficiency.

O'Leary's response to that sort of complaint in the Financial Times has now claimed the top spot on my list of favourite quotes from chief execs, for its wonderful candour.

"Ryanair is noisy, full and we are always trying to sell you something, " he said. "If you want a quiet flight, use another airline."

It's important to touch on a couple of points about this.

First on safety. You might legitimately be wondering, "What's the deal? Were we being lied to when we were told all those years that it wasn't safe to use a mobile on a plane?"

Well there's a lot of debate about that, but the company supplying Ryanair the widgets to make the phones work on the planes has more or less solved the problem, they say. Basically when your phone is looking for a signal from a mobile network mast on the ground, it pumps up the radio signal hugely trying to stay connected. By having only to connect to a little wire above your head, your phone generates a lot less signal and uses a lot less power.

Second is that O'Leary has given us a near-perfect locution of what the company is and what it stands for. Ryanair promises a bus service in the sky and does what it says on the tin.

For years, as it snapped up planes from Boeing at a post9/11 discount, it was Europe's fastest-growing airline. Now it's the biggest. It is at least as much the national airline of modern Ireland as Aer Lingus.

Ryanair connect more people to family and friends that they wouldn't otherwise be able to afford to see. They help small businesses keep up a travel schedule to drum up business from customers that only big companies could when it cost hundreds of pounds to fly to the continent or just London. They won't talk up that warm fuzzy stuff, but it's real nonetheless.

What does this mean for Aer Lingus? The company will this week start pitching itself to potential investors by arguing that Aer Lingus is a Tesco to Ryanair's Aldi. Aer Lingus can define itself as the middle-brow alternative, in other words, for those people willing to pay a little bit extra to avoid some howya in the next, very small, seat yammering into a hot pink phone about the "dedly buzz" from last night. And there are plenty of Irish people who will. But that positioning couldn't exist without a Ryanair.

But really, if investors buy the Aer Lingus story, they will also be buying into a company that has transformed itself by learning to become leaner.

And it's no secret that all they had to do to figure out ways to be leaner, without being meaner, was to walk a little further away from the check-in desk at Dublin Airport and take a Ryanair flight.