There's nothing like a spell in the Caribbean to offset the autumn nip and one man who must be enjoying the heat is Mr Garry Cullen, former chief executive of Aer Lingus.

Mr Cullen, who quit the State-owned company last March, now runs a small airline in Antigua. Those he left behind at Aer Lingus felt a different sort of heat last Tuesday - 20,000 passengers missed their flights because the fleet was grounded when cabin crew affiliated to the trade union IMPACT walked off the job.

This was bad news indeed for the airline, which hoped to float on the stock exchange in June. Mr Cullen's reluctance to lead that process prompted his resignation. With Aer Lingus now mired in industrial turmoil and the flotation put off until April next, certain senior figures have joked that he made the right move.

His successor, Mr Michael Foley, may not have anticipated grounded aircraft and picketers claiming "we work in the air, we can't live on it" within a month of his arrival. Yet he knew the question of cabin crew pay - and rates earned by four other worker groups at the airline - had been simmering for months.

If a breakdown in pay talks between managers and IMPACT last Friday week led to Tuesday's stoppage, it is but one of five ongoing disputes which are at various stages in the industrial relations process.

In addition, SIPTU and IMPACT, the company's two largest trade unions, are in dispute over the affiliation of cabin crew.

The roots of the current difficulty at Aer Lingus go back to its near-collapse in the early 1990s. With internal weaknesses almost fatally exposed by a worldwide slump in the airline business which followed the Gulf crisis, the company was rescued from the brink by a recovery programme developed by its chairman, Mr Bernie Cahill.

Mr Cahill's plan, finalised in 1994, contained the following elements: a pay freeze; casualisation at certain grades; 1,000 redundancies; the granting of a 5 per cent share in Aer Lingus to workers; a £250 million disposal of non-core assets and a £175 million capital injection from the Government.

Its success, which has seen Aer Lingus record strong profits and growth in recent years, means the company's survival is no longer in question.

Growing the business is now the priority, though this requires money.

The Government's line - as explained again in the Dail this week by the Minister for Public Enterprise, Ms O'Rourke - is that the EU will not permit it to advance more capital to the company. Ms O'Rourke said: "Aer Lingus must also maintain viability under EU rules. When we got permission for the money in 1994, we were clearly told it was the last cash injection that could be put into Aer Lingus."

The policy now is to float the company and raise some £200 million to fund its expansion in an issue of new shares.

However, Eircom's poor performance on the stock exchange has led to uncertainty surrounding the flotation of other public assets.

But, at least in theory, a flotation of Aer Lingus would enable ordinary people to buy into the company before it is sold on to a larger airline.

Senior figures at the State company see it being absorbed into a larger operation in the long term. With consolidation in the business expected, few observers think that small national carriers such as Aer Lingus will have a future when ever-larger airlines dominate the industry.

Global alliances - such as the OneWorld grouping joined this year by Aer Lingus - allowing airlines to link their ticketing systems are seen as a precursor to this consolidation.

The theory goes that small airlines will be absorbed by larger players or put out of business once the regulatory systems in Europe and the US facilitate the large-scale international takeovers and mergers seen in almost every other major industry worldwide.

If that is the backdrop, the stoppage this week - and associated problems - are more closely linked to practicality than theory.

Pay is the key issue. Given the company's turnaround - its pretax profit last year was £60 million, after exceptional items - staff argue that the concessions granted under the Cahill plan should be unwound.

That the economy is booming and prosperity is causing prices to rise is an additional factor.

The groups who have submitted pay claims are clerical staff, catering workers, baggage-handlers, pilots and cabin crew.

While clerical staff have threatened action and caterers and baggage-handlers have interrupted work, causing delays, only the stoppage by cabin crew has caused flights to be cancelled.

Here an inter-union dispute between SIPTU and IMPACT is crucial. The problem emerged earlier this summer when a committee of cabin crew sought to switch membership from SIPTU to IMPACT, which represents Aer Lingus pilots and management.

The committee, led by Ms Nora O'Reilly, alleged it received a poor service from SIPTU and claimed officials at the union were "too close" to management. SIPTU disputed this and argued that IMPACT should not accept cabin crew into the union. When it became clear that IMPACT was willing to accept cabin crew, the matter was referred to the Irish Congress of Trade Unions for conciliation.

A report for ICTU by Mr Gerry Durkan SC suggested that the 1,026 cabin crew workers who were already paying subscriptions to IMPACT by September 29th should stay with that union. The remaining group of about 600 should stay with SIPTU, it said.

SIPTU will accept this, according to its aviation secretary, Mr Tony Walshe.

However, IMPACT's assistant deputy secretary, Mr Shay Cody, claims 1,450 cabin crew have joined his union.

Aer Lingus wanted to deal with only cabin crew recognised by ICTU in pay talks last Friday and claimed this is what led to the breakdown.

IMPACT claimed Aer Lingus's refusal to refer the matter to the Labour Relations Commission (LRC) forced it to go forward with the strike action it had previously threatened.

Either way, cabin crew went on strike last Tuesday. By the end of the day, when the cancellation of 200 flights led to losses of £2 million, Aer Lingus had agreed to enter talks at the LRC last Thursday. This process, chaired by Mr Kevin Foley, a conciliation official, will continue next week.

AER LINGUS does not deny that cabin crew and some other workers are poorly paid. The starting hourly rate is £5 for a 20-hour week, marginally above the national minimum wage of £4.40 per hour.

"Our overall position on pay is that we accept there is an issue to address, particularly a low pay issue," said a spokesman.

He warned, however, that the increases demanded would be unsustainable. The company's payroll costs £200 million per year. When combined with increases under the Programme for Prosperity and Fairness the claims would cost £40 million, against total profitability of £48 million.

Crucial here is the pay claim of pilots, who want parity with their counterparts in the OneWorld alliance, which includes British Airways and American Airlines.

This would involve pay rises well in excess of 50 per cent, although Mr Foley has argued that such demands are unrealistic.

As one observer noted, workers will suffer if they force pay rises that the airline cannot afford. This is because staff stand to gain an additional 9.9 per cent stake of the airline.

This would bring their total shareholding to 14.9 per cent. Yet its potential value would be diminished if Aer Lingus was saddled with an overbearing cost burden.

Whether the company could be floated in this context is another matter.

As the 500,000 people who invested in Eircom know, the stock market is an unforgiving place with an unyielding eye on the bottom line.