Update 4.25pm: Ryanair will be issuing another list of cancelled flights tomorrow, the airline has announced.
"Cancellation notices for flights cancelled up to and including Wednesday 20 Sept have been sent to affected customers and posted on the Ryanair.com website," said Ryanair's Kenny Jacobs.
"We will continue to send regular updates and post flight information on our website, with the next set of cancellations to be issued on Monday."
Update - 1.59pm: Furious Ryanair travellers have demanded that the budget airline provide immediate clarity over cancelled flights.
The airline has only published a list for Sunday despite announcing cancellations of between 1,500 to 2,000 flights over the next six weeks.
Four Dublin flights are among 82 flights cancelled today.
The airline said it sent an email to anybody who was booked on a flight up to and including Wednesday September 20 which has been cancelled but it has not said when people are booked to travel after that date will be notified.
Passengers have accused the airline of treating them "appallingly" and demanded it publishes a full list of the flights to be cancelled over the next six weeks.
Grandmother Karen Litton was due to fly from Knock to Stansted to meet her first granddaughter on Wednesday.
However, the estate agent has been left devastated after Ryanair cancelled her flight.
"I am heartbroken.
"I was due to fly over to meet my new granddaughter Margot on Wednesday.
"I was going to spend a week with my daughter to help out as her husband is starting back to work after his paternity leave. We are all so disappointed," she said.
Mrs Litton said she has been unable to contact the airline to re-book her flights or apply for compensation.
"It is very frustrating. Everything seems to have just physically shut down.
"Every time I try to go on the website to re-book flights it doesn't let me.
"I have tried to submit a claim form but it won't let me put in my flight number. And the live help facility has been withdrawn.
Your flight is operating as scheduled unless you have received a cancellation email. List of flights affected: https://t.co/g9YyVNtWoZ— Ryanair (@Ryanair) September 16, 2017
"I would fly Ryanair about once a month. I was always very pro Ryanair.
"Knock airport is just a 40 minute drive away for me and their times always suited me but how they are treating people now is a disgrace.
"There are people in much worse situations than myself.
"There are young girls stranded in foreign countries, maybe with no extra money or credit cards. Customers are being treated appallingly."
Many passengers have taken to social media in an attempt to contact Ryanair to find out if their flights have been cancelled.
"It is just disgraceful that Ryanair won't tell people if their flights have been cancelled.
"A full list should be made available immediately so that people can make alternative plans," said Mrs Litton.
Earlier: Ryanair passengers are again facing major travel disruption today after cancelling up to 50 flights a day for the next six weeks.
Flights departing Dublin today for European destinations such as Amsterdam, Frankfurt and Nantes have all been cancelled.
Ryanair has apologised and promised to rearrange or refund flights.
The budget airline says flights are operating as scheduled unless an email confirming a cancellation has been received.
Brian Higgins, from the Commission of Aviation Regulation, has this advice: "The best thing to do at the moment is to check the homepage on our website and we've details in our article headed under "Ryanair Flight Cancellations".
"In a few lines it spells out what customer entitlements are in that particular situation."
The articles in question reads:
"If you have been affected by the Ryanair programme of flight cancellations you are entitled to a choice of refund or rerouting. Compensation may also be payable depending on the notice period Ryanair has given you.
More information on your rights as a passenger when your flight is cancelled is available here.
Passengers who remain unclear about their entitlements as set out in EC Regulation 261/ 2004, or who have further queries in relation to same, should contact this office at firstname.lastname@example.org or on 1890 787 787 or + 353 1 6611700."
Below is the list of Irish flights which have been cancelled by the airline for today.
Kenny Jacobs, chief marketing officer, said the company was "working hard to fix" the problem, after it announced a 2% reduction in scheduled flights until the end of October.
He said: "We apologise to all affected customers for these cancellations. We have messed up in the planning of pilot holidays and we're working hard to fix that."
Ryanair said air traffic control (ATC) delays and strikes, bad weather and a backlog of annual leave to be taken by pilots and cabin crew had led to punctuality falling to below 80% over the last two weeks.
A spokesman said this figure was "unacceptable" and the company has apologised to affected customers, who it said will be offered alternative flights or refunds.
Ryanair said a change in the company's holiday year, from April to March to a calendar year from January 1 2018, had seen an increase in holiday allocations as staff used their annual leave before the end of the year.
It said the 40 to 50 flight cancellations each day accounted for less than 2% of its 2,500 daily flights and it would create additional standby aircraft to help restore punctuality.
Mr Jacobs said a "slightly higher number" of flights would be cancelled this weekend.
Robin Kiely, head of communications at Ryanair, said: "We have operated a record schedule and traffic numbers during the peak summer months of July and August but must now allocate annual leave to pilots and cabin crew in September and October while still running the bulk of our summer schedule.
"This increased leave, at a time of ATC capacity delays and strikes, has severely reduced our on-time performance over the past two weeks to under 80%. By cancelling less than 2% of our flying programme over the next six weeks, until our winter schedule starts in early November, we can improve the operational resilience of our schedules and restore punctuality to our annualised target of 90%.
"We apologise sincerely to the small number of customers affected by these cancellations and will be doing our utmost to arrange alternative flights and/or full refunds for them."