Profits at Aer Lingus and British Airways owner IAG grew by over 6% in the second quarter of 2019, the company's latest results show.
IAG outperformed forecasts, recording an operating profit of €960m in the three months to June 30, up from €900m in the same period last year.
Profits are down for the first half of the year however, dropping €145m amid a 20.5 % increase in fuel and oil costs and emissions charges and a 5% rise in employee costs.
Passenger revenue across the group grew by 7.2 % in the first six months of the year, from €9,938m in 2018 to €10,649m this year, with passenger numbers up by 6%.
"Despite fuel cost headwinds, we delivered a good performance," Willie Walsh, IAG Chief Executive Officer, said.
"At constant currency, fuel unit costs were up 6.3% while passenger unit revenue increased 1.1%, benefitting from the timing of Easter."
Operating profit at Aer Lingus, meanwhile, fell from €104m in the first six months of last year to €78m in 2019.
Aer Lingus CEO Sean Doyle said the results represented a solid performance in a challenging market.
"We continue to focus on delivering further cost efficiencies for the business in order to improve our competitiveness," he said.
"The challenges being experienced throughout the European Short Haul market underline the need for Aer Lingus to focus on improved competitiveness."
Speaking RTÉ's Morning Ireland, Mr Walsh defended Aer Lingus' support of a reduction in Dublin Airport's passenger charge, which has been proposed by the Commission for Aviation Regulation.
The reduction has been criticised by the DAA, which says it will impact on its funding plans for the airport.
"It's the regulator who has done a detailed assessment of the airport's ability to invest and it clearly said that they can fulfill all of the investment criteria, maintain an investment-grade credit rating and delivery the infrastructure that's required," he said.
"This is very simple; we want to grow at Dublin, the transatlantic performance by Aer Lingus is very, very good, the Irish economy is benefitting significantly from this.
"We want to add more routes and more destinations, we want to add more capacity and bring more American business and tourism into Ireland. We can only do that if the airport is pragmatic and we think they should just get on with it."
IAG said it expected the group's full-year profit to be in line with last year and said passenger unit revenue and non-fuel costs would both improve for the rest of the year.
Mr Walsh also said that the company had a plan in place for a no-deal Brexit and it was now up to national regulators across the European Union to decide whether they were acceptable.
In a note to investors, Goodbody analyst Mark Simpson said:
"Given all the uncertainties over global growth and Brexit, this looks to be a very strong statement by the company and implies that forward bookings are trending well."