By Anna Wlodarczak-Semczuk

WARSAW (Reuters) - Ryanair could have as many as 5 million passengers per year in Ukraine within a year or two of reopening its skies, CEO Michael O'Leary said on Tuesday, as the low-cost airline prepared for a return to the war-torn country.

With U.S. President Donald Trump vowing to bring the war in Ukraine to an end soon, airlines including Ryanair and its low-cost competitor Wizz Air are getting in position to benefit from flights resuming.

"Straight out-of-the-box... we have two million seats in there within six weeks (of the sky reopening) and then I think we would want to open bases both in Kyiv and Lviv within 12 months and then I think we could go from two to five million passengers within a year or two," O'Leary told Reuters.

He said returning to some other airports in Ukraine could take longer due to greater damage from the three-year war between Russia and Ukraine. He said that the airline wanted to have 6-8 routes to Ukraine from Poland.

Ryanair will launch 24 new routes from Poland this summer. It expects summer fares overall to rise 4-6% this year, O'Leary said at a press conference in Warsaw on Tuesday.

The Irish airline experienced a 10% fall in fares over its two summer quarters last year, in part due to a dispute with online travel agents, which has been largely resolved.

"Fares will grow between 4% and 6% this year, so you'll still be traveling at slightly cheaper prices than in the summer of 2023, but you'll be a little bit up on 2024," O'Leary said.

He thought the situation at Boeing was improving and that the planemaker would catch up on its delivery backlog in time for summer 2026.

"They're going to leave us 20 aircraft short for the summer of 2025, but we are due 29 aircraft for summer 2026, 24 of those aircraft will be delivered in August, September or October of 2025 so we're guaranteed to have them for summer 2026 and then the last four are due in January and February of 2026," he said.

(Reporting by Anna Wlodarczak-Semczuk, writing by Alan Charlish; Editing by Kirsten Donovan and Bernadette Baum)