The Irish firm said costs in its “sales, marketing and other” bracket leapt 30%, as it dished out compensation after around 700,000 customers were disrupted by cancelled flights stretching from September to October.
The low-cost carrier has come under fire after cancelling around 20,000 flights in the autumn due to an error over pilot holiday rosters.
Despite the hit, pre-tax profits climbed to 1.293 billion euro (£1.139 billion) for the six months ending in September, up from 1.168 billion euro (£1.029 billion) over the period last year.
The jump was driven by a strong Easter period, helping bolster customer numbers by 11% to 72.1 million.
Revenues also picked up 7% to 4.425 billion euro (£3.899 billion), as it added 80 new routes and drove down air fares by 5%.
Chief executive Michael O’Leary said: “These strong H1 results reinforce the robust nature of Ryanair’s low fare, pan-European growth model, even during a period which suffered a material failure in our pilot rostering function in early September.
“Prior to this event, we were on track to deliver strong H1 results during which we opened three new bases and 80 new routes.
“We took delivery of 35 new B737s in the first six months of 2017, we stimulated 11% traffic growth with 5% lower airfares, and achieved an industry record load factor of 97% in the peak summer months.”