Ryanair was accused of falsely claiming it did not have to re-route passenger on other airlines, particularly when there are no other services available.
The CAA said Ryanair also stopped short of providing details on its obligations to refund additional expenses incurred by passengers as a result of cancellations and re-routing.
Those expenses include meals, hotels and transfer costs, the CAA explained.
There are clear laws in place, which are intended to assist passengers in the event of a cancellation, helping minimise both the frustration and inconvenience caused by circumstances completely out of their control.
We have made this crystal clear to Ryanair, who are well aware of their legal obligations, which includes how and when they should reroute passengers, along with the level of information it provides its passengers.
The information Ryanair published today again fails to makes this clear.
In expediting our enforcement action we are seeking to ensure that Ryanair's customers will receive the correct and necessary information, to make an informed choice about an alternative flight.
– ANDREW HAINES, CAA CHIEF EXECUTIVE
The flights have been axed after rostering errors meant the airline had allowed too many pilots to go on leave at the same time, meaning the company now has a shortage.
Taking more flights out of service means that the Irish carrier will be able to "roster all of the extra pilot leave necessary" for the rest of 2017.
Since the initial announcement was made, 2,000 flights have already been grounded, costing the airline almost £22 million.
Free flight vouchers for affected passengers are thought to cost the airline an extra £22 million.
Which routes will be axed from November 17?
- Edinburgh – Szczecin
- Glasgow – Las Palmas
- London (LGW) – Belfast
- London (STN) – Edinburgh
- London (STN) – Glasgow
- Newcastle – Faro
- Newcastle – Gdansk
- Hamburg – Edinburgh
- Bucharest – Palermo
- Chania – Athens
- Chania – Pafos
- Chania – Thessaloniki
- Cologne – Berlin (SXF)
- Gdansk – Warsaw
- Hamburg – Katowice
- Hamburg – Oslo (TRF)
- Hamburg – Thessaloniki
- Hamburg – Venice (TSF)
- Sofia – Castellon
- Sofia – Memmingen
- Sofia – Pisa
- Sofia – Stockholm (NYO)
- Sofia – Venice (TSF)
- Thessaloniki – Bratislava
- Thessaloniki – Paris BVA
- Thessaloniki – Warsaw (WMI)
- Trapani – Baden Baden
- Trapani – Frankfurt (HHN)
- Trapani – Genoa
- Trapani – Krakow
- Trapani – Parma
- Trapani – Rome FIU
- Trapani – Trieste
- Wroclaw – Warsaw
What should affected passengers do?
Affected passengers will have received an email.
They will be offered an alternative flight or a full refund.
Despite the high number of cancellations, only 1% of passengers have been affected.
Customers whose September and October flights have been cancelled will have received a £35 one-way or £80 return Ryanair travel voucher.
Under EU law, passengers given less than 14 days notice of a flight cancellation are entitled to claim compensation worth up to 250 euros (£221) depending on the timing of alternative flights and if the issue was not beyond the responsibility of the airline, such as extreme weather.
Speaking last week, Michael O'Leary, chief executive of the budget airline said: "If they're [customers] not satisfied with the alternative flights offered they can have a full refund and they will all be entitled to their EU261 compensation entitlements.
"We will not be trying to claim exceptional circumstances.
"This is our mess-up. When we make a mess in Ryanair we come out with our hands up.
"We try to explain why we've made the mess and we will pay compensation to those passengers who are entitled to compensation, which will be those flights that are cancelled over the next two weeks."