British Airways owner International Airlines Group (IAG) has warned that strikes in France are posing a challenge to its operations.
The airline group, which owns Aer Lingus, Vueling and Iberia, said strikes were causing disruption for customers and hurting the Spanish economy.
The firm has joined forces with other carriers to complain about the strikes to the EU.
Willie Walsh, IAG’s chief executive, said: “Unfortunately, French air traffic control strikes continued to challenge our airlines’ operations, causing disruption to our customers.
“Vueling was particularly affected and incurred an additional 20 million euros (£17.8 million) of disruption costs in the quarter.
“These strikes are also having a significant impact on the Spanish economy and tourism.”
In the six months to June 30, operating profit, before accounting for exceptional items, was up 17.4% to 1.12 billion euros (£1 billion).
Total revenue rose 3.1% to 11.2 billion euros.
Liberum analysts said IAG was one of the few airlines that would achieve profit growth this year.
“Although the trading environment may not be as supportive as last year, with toughening unit revenue comparatives and rising fuel prices, we see IAG as the best positioned of the network carriers to deal with these potential challenges,” they said.
IAG’s figures come after Mr Walsh co-ordinated legal action with easyJet, Ryanair and Wizz Air to complain to the European Commission about strikes in France.
The airlines have claimed that France’s strikes breach the “fundamental principle of freedom of movement within the EU”, having already caused tens of thousands of flights to be cancelled this year, impacting millions of passengers.
They alleged that France is breaking EU law by not enabling flights over the country during strikes, denying passengers their fundamental freedom to travel between member states not affected by strike action.