The budget airline was told it could face legal action by the UK's Civil Aviation Authority (CAA) following a decision to ground 18,000 aircraft until March next year.
He said he welcomes the commitment but is "disappointed" that the carrier has yet to respond to a request made on September 21 for clarification on how Ryanair will help the customers affected by its cancellations.
Ryanair failed to take care of thousands of customers affected by its flight cancellations and is deliberately violating European air passengers' rights under regulation EU261.
The Irish low-priced airline will finalize 25 of their 400 aircraft between November and March 25 to eliminate the "possibility" of being forced to "cancel more flights" in the future.
Ryanair boss Michael O'Leary last week sought to address the airline's problems with a first wave of 315,000 cancellations.
Ryanair says if it can not offer a flight on the same or next day from the original or "suitable alternative airport", it will book passengers onto flights by either easyJet, Jet2, Vueling, CityJet, Aer Lingus, Norwegian or Eurowings airlines.More news: Chelsea Manning says she has been barred from entering Canada
The CAA has told the Irish carrier to correct its compensation policy for passengers after mass flight cancellations arising from the mismanagement of pilot holiday.
"We apologise again sincerely for the disruption and inconvenience our rostering failure has caused some of our customers", Ryanair's Chief Marketing Officer said in the notice.
Affected passengers were emailed with two options: a refund, or re-booking on a different Ryanair flight.
Ryanair has cancelled more than 450 flights out of Dublin between November and March.
The warning said the company had until 5 p.m. Friday local time to put in place an "orderly explanation" about re-routing and reimbursement of expenses after a string of cancelled flights. Ryanair claims this move will eliminate the risk of further flight cancellations because "slower growth creates spare aircraft and crews across Ryanair's 86 bases".
Earlier: The Taoiseach has said he expects Ryanair to ensure that passengers' rights are protected.
"So if anyone has had a flight cancelled, any airline - in this case Ryanair - needs to provide them with an alternative way of getting to where they need to go or refunding them in full".