Ryanair suffered half-year losses of almost €200 million as Covid-19 grounded its entire fleet from mid-March until the end of June.
Carryings in the six months to September 30 fell 80% to 17 million from 86 million in the same period last year.
Ryanair warned that the rest of the financial year will continue to be “hugely challenging”.
The carrier also expects Brexit to cause “adverse trading consequences”.
While flights were resumed on July 1 at up to 60% of capacity, passenger confidence and forward bookings were “negatively impacted by the return of uncoordinated EU government flight restrictions in September and October”.
The curbs “heavily curtailed” travel to and from much of central Europe, the UK, Ireland, Austria, Belgium and Portugal, Ryanair said while reporting a loss of €197 million for the period.
As a result, the low cost airline group recently cut its full year traffic guidance to about 38 million passengers, with winter capacity cut to “at most” 40% of last year.
But the guidance could be further revised downwards if EU governments “continue to mismanage air travel and impose more uncoordinated travel restrictions or lock downs this winter”.
The group expects to record higher losses in the winter than in the six months to September.
Ryanair insisted that “almost all” refund requests have now been dealt with either via cash refunds or vouchers, “despite the enormity of the task”.
“This process was frustrated by unlicensed OTAs, many of who provided false customer contact and fake payment details at the time of booking,” the carrier claimed.
The Irish airline group said: “As we look beyond the Covid-19 crisis, and the emergence of effective vaccines in early 2021, the Ryanair group expects to have a lower cost base, a stronger balance sheet, which will enable it to fund lower fares, and add new lower cost aircraft to capitalise on the many growth opportunities that will be available in all markets across Europe, especially where competitor airlines have substantially cut capacity or failed.
“The risk of a no-deal Brexit remains high. We hope, before the end of the transition period in December, that the UK and Europe will agree a trade deal to cover air travel which will allow the free movement of people and the deregulated airline market between the UK and Europe to continue.
“As an EU airline group, Ryanair should be less affected by a no-deal Brexit than our UK registered competitors.”
The carrier added: “We expect intra-European air travel capacity to remain subdued for the next few years. This will create opportunities for Ryanair to grow its network, and expand its fleet, to take advantage of lower cost airport and aircraft opportunities that will inevitably arise.”
The airline hopes to start taking delivery of its first Boeing 737 Max in early 2021 following the global grounding of the new generation aircraft in March 2019 after two fatal crashes.
“We expect to take delivery of approximately 30 Maxs before peak summer 2021,” Ryanair said, adding that it remained committed to the new “game changer” aircraft.
The Max will have 4% more seats, 16% lower fuel burn and 40% lower noise emissions than current 737s in its fleet.
“These new aircraft will enable Ryanair to grow to 200 million passengers per annum over the next 5 or 6 years while lowering the cost base and significantly reducing its environmental footprint,” the group said.