Aer Lingus is considering compulsory redundancies and is reviewing its operations in Cork and Shannon Airports.
In a communication to staff today, seen by RTÉ News, the airline's chief executive Sean Doyle said that previously announced job cuts "will be implemented on a voluntary basis if possible, but on a compulsory basis if necessary."
He went to say that the airline has "no line of sight" on what was described as "meaningful resumption" of its operations in Cork and Shannon Airports.
"As such we are reviewing the scale of our flying programme from these airports and the ongoing viability of our regional bases there," Mr Doyle said.
Last month Aer Lingus announced that up to 500 jobs could go at the airline as it continues to cope with the impact of the coronavirus.
"The catastrophic impact of Covid-19 on the aviation sector has been compounded in Ireland by the implementation of the most restrictive travel policies in Europe and the failure to implement supports for the sector," the airline said in a statement today.
"Aer Lingus has also not made the required progress on the implementation of industry standard work practices with key cohorts of employees. In this context and given the Aer Lingus quarterly results today, significant redundancies are required across the business," the airline added.
Aer Lingus today recorded an operating loss of €316m for the six months to the end of June compared to an operating profit of €78m the same time last year, figures from its parent IAG show today.
The airline said its passenger revenues fell to €315m from €936m last year.
SIPTU has said it will not entertain compulsory redundancies "in any circumstances".
Speaking on RTÉ's Drivetime, SIPTU Aviation Sector Organiser Neil McGowan said the mood in Aer Lingus was "rock bottom" right now, and had been since the outset of the pandemic.
He said it was "wholly inappropriate" for the video from the airline's chief executive to be released at a time when a consultation process was undertaken with the airline, and said their time would be much better used in engaging with the union towards a voluntary redundancy scheme.
He said such videos were becoming the norm and should not be. He said throwing the idea of compulsory redundancies out there was no way to go about any negotiation.
He said the company is losing between €1.5m to €2m a day due to Covid-19 and said the government needed to step in.
He said the government has been "asleep at the wheel" in terms of supporting workers in the aviation industry, adding that if they don't step in, then we will not have a functioning aviation sector post-Covid.
He said for an island economy, that could not be allowed to happen.
Mr McGowan said SIPTU has been through a very difficult period in terms of negotiations with the airline, but said both parties need to remain responsible.
He said it has been "an exceptionally difficult time" in Aer Lingus, but we needed to come out on the other side with the airline intact.
IAG chief executive Willie Walsh has said Aer Lingus will continue to exist with the support of its parent group, but it will be a smaller airline with fewer people working for it due to the ongoing impact of Covid-19.
Mr Walsh said the planned redundancies at Aer Lingus were "deeply regrettable" but "inevitable" and that even if restrictions were relaxed somewhat now, it was too late to prevent them.
Mr Walsh also dismissed the notion that the Irish carrier could be sacrificed in order to protect its larger stable-mates.
"That's not the way the group operates - Aer Lingus operates standing on its own two feet, it's clearly been a strong performer within the group over the past number of years," he said.
"The losses in Aer Lingus are dreadful, they're shocking but they're shocking for every airline in the industry."
He said the current trading conditions were by far the worst ever faced by Aer Lingus - and the rest of the industry - even compared to the market in the immediate aftermath of the September 11th terrorist attacks.
"If you want to put it into context - the second quarter operating loss for Aer Lingus was €98m, now that compares to the loss in 2001 of €52m for the full year," Mr Walsh said.
"I think everybody remembers just how challenging 2001 was for Aer Lingus, so this is clearly a very challenging period."
However, he said, every effort was being made to reorientate the business to fit the current outlook.
"The management team [in Aer Lingus] know what needs to be done, I think they're working very closely and very well with the employees in the business to try and do everything that is required to ensure that they can, not just survive through this downturn, which is the deepest one we've ever witness in the industry, but to make sure that we're in a position to be competitive once we come through this."
During the second quarter, IAG said that capacity at Aer Lingus was driven by cargo needs with flights operating regularly to New York, Chicago and Boston in addition to flights from China carrying back Personal Protective Equipment (PPE).
Speaking in a conference call to reporters, Willie Walsh was also highly critical of the current government travel advice here.
He said people should not have to isolate for 14 days just because they had been flying.
Government advice should be "more targetted" and "more balanced", according to the IAG CEO, as he described the government restrictions on international travel as "more extreme than in other parts of the world".
He also described Covid-19 as a serious challenge and warned that it was not temporary and that societies need to adapt.
If restrictions on air travel were to continue, he said that any plans Aer Lingus had to invest in its fleet and network "would be scrapped".
Additional reporting from Adam Maguire and Glenda Sheridan