6am

Dermot Mannion wakes after what can barely be described as a night's sleep.

The man who is about to become the first boss of an airline to seek a London stock market listing since easyJet six years ago didn't get his head down until 3am. Before that, the chief executive of Aer Lingus was stuck in a pricing meeting to determine how much Ireland's national flag carrier would be worth as a public company. "It reminded me of an election count. You got orders [for the stock] coming in like votes on an election night," he says.

As well as valuing the group, its advisers had to carve up the group's stock between the airline's bevy of local supporters, staff members and international institutions, all keen to back the long-awaited IPO.

7am

Anxious, as ever, not to be delayed (a true airline boss) he is out of his house in Howth, to Dublin's north, within 15 minutes and is quickly heading for the broadcasting studio opposite the Dail for the first of five back-to-back interviews.

Aer Lingus has already been plastered all over the news this week - and not solely because of the float. In a handy quirk of timing, the IPO came just three days after the Ryder Cup, which was played at the K Club in Kildare, and which Aer Lingus sponsored. The carrier's shamrock was emblazoned across television screens and newspapers from New York to Paris: it flew the winning European team in and out of the Irish capital.

8am

The moment of truth catches Mr Mannion when he is back on the road en route to the airline's base at the city's airport. Now is when the carrier, whose Gaelic name meaning "air fleet" is the same as Russia's Aeroflot, will learn how highly it is valued by the financial world.

That it has made it to the market at all is a testament to 48-year-old Mr Mannion's powers of negotiation, with the Irish government as well as the industry's powerful trade unions. His predecessor, Willie Walsh, now in the cockpit at British Airways, quit abruptly along with two senior colleagues last year after failing to push the float through. It took promises on slashing the pension deficit, job security and ambitious growth plans - the airline's €500m (£338m) flotation proceeds will be used to help fund a €2bn fleet expansion - to get the IPO plans rubber-stamped.

In the end, the shares were priced at €2.20 (£1.48), at the bottom end of the €2.10-to-€2.70 range set before the roadshow. Pricing is an inexact science at the best of times, never more so than in the wake of the foiling of an alleged international bomb plot, a nervous IPO market, and the delay to a new "open skies" agreement between the Irish and US governments. Aer Lingus is counting on the latter to increase the number of US cities to which it can fly from four to as many as 15, so it was a relief when the shares opened as hoped - up on the offer price.

"I was getting lots of text messages especially from my former colleagues in Dubai at Emirates [the Gulf carrier that Mr Mannion helped to turn into the world's fastest-growing long-haul airline before he got the call from Dublin] who have taken a great interest in what's been going on here. They were particularly pleased."

Contrary to many pre-flotation rumours, Emirates did not emerge on the Aer Lingus shareholder register, and "nor would I expect them to", Mr Mannion says. "I wouldn't expect any takeover offer, either. The chance is remote in the extreme."

9.30am

It's Mr Mannion's first appearance in the office in a fortnight as he's been on a whistle-stop tour of the main financial capitals trying to woo potential investors. "I said to the first person I saw, 'My name is Dermot Mannion. You might remember me. I used to work here'." It's also his first opportunity of the day for a cup of coffee; he has relied on pure adrenaline to keep him going up until now.

In the canteen he learns that the staff accessory of the day is a calculator. "Everyone was tapping away, working out how much their shares were worth." Aer Lingus employees were left owning 12 per cent of the company, less than the 14.9 per cent they had before, but the flipside is that they can now actually trade the stock. (The Irish government was left with a 28 per cent stake; institutions got 40 per cent, and retail investors 12 per cent.)

Mr Mannion spends the morning catching up on paperwork, doing another round of press interviews and then, with a four-minute window before a top-team photo shoot to mark the day, he grabs some fresh air, strolling around the airport grounds.

Running the national flag carrier has raised his profile sky high, especially given the decision to include private shareholders in the offering. He recalls being stopped when walking though Dublin airport by a "very polite little old lady. She said, 'Excuse me, are you Dermot Mannion? Well, people like me, who have lived for a long time, really value the shamrock [on the fleet's tail fins]. Whatever else you do with Aer Lingus make sure you don't take the shamrock off'."

1pm

He is back in the canteen for lunch, where he eats every day. It's over an Irish stew, or such like, that he gets the most feedback from members of staff "who are certainly not afraid to come up and talk to me about things that are going well or not so well".

Today, the atmosphere is positively party-like. "They're a jolly bunch. Everyone was in extremely good humour." Celebratory bubbles have to wait until later, though. Despite the successful float, which valued the carrier at about €1.2bn, it's a dry day for the Irishman. (Even at the drinks party later, champagne is off the menu. "We're a low-cost airline, you know!").

2pm

Keen to reinforce the old axiom of "the more things change, the more things stay the same", there is a long-overdue executive meeting. On the agenda is improving the Aer Lingus website - so that passengers can choose their seats before flying - and assessing that Ryder Cup sponsorship.

The "open skies" issue also comes up. That transatlantic travel was not freed up in time for the IPO was a bit of a setback. Mr Mannion wants the so-called "Shannon stopover" clause that requires an equal number of flights that go via Dublin and the US and Shannon and the US to be to be amended to a ratio of three to one in favour of Dublin. He hopes to secure a new deal "before the end of this calendar year".

There is also time, later on, to squeeze in one of the new cabin crew meetings. It's a drawback for the aviation industry that their key employees are, by necessity, somewhat removed from head office, so it can be a struggle keeping them in the loop. Unlike his predecessor, Mr Mannion was not a pilot; he worked his way up through the industry through various financial roles, culminating in finance director of Emirates.

5.15pm

He calls it a day to give himself time to drive the 45-minute commute back home so he can shower and change before the evening's festivities. Having missed his family summer holiday - "it was a big sacrifice and big disappointment for everybody" - he also needs to think about what to pack for the two-week break that he and his wife are about to grab in the US. Sadly for his four kids, it's already term-time for them.

A little more than 24 hours after that pricing meeting began, he is back in Dublin's financial services district to host a drinks party along with his chairman, John Sharman, to celebrate.

"It was very, very low key - just a few glasses of wine and a few beers - and a very nice end to a hectic day." And definitely no champagne.