Ryanair Holdings posted a 16 per cent rise in first-half underlying net profits to €175.5 million to surpass market expectations.
The budget airline said adjusted earnings per share also rose by 16 per cent to 23.21 cents in the six months to the end of September.
"Looking forward for the remainder of the fiscal year, we remain confident that traffic growth will continue to be strong, but cautious about fares and yields," said Ryanair chief executive Mr Michael O'Leary.
"We expect that average yields will continue to decline by between 10 and 15 per cent compared to those charged last year."
The airline has been expanding aggressively, bringing in new planes and opening new routes, in a bid to grow its passenger volume to 24 million this year from some 15 million last year.
However, the company has repeatedly said it expects to earn less money per passenger carried as it cuts fares to fill the huge numbers of additional seats.
The latest results are likely to be overshadowed by a European Commission inquiry into whether the airline received illegal state subsidies at its Belgian hub of Charleroi, in what could prove a test case for the industry. A decision is expected later this month.