International Airlines Group passenger carryings rose by a strong 19.4% in January to 6.3 million.
The British Airways, Aer Lingus, Iberia and Vueling parent company saw overall premium traffic rise by 2.1% year-on-year.
Group capacity was up by 9.4% over the same month last year.
European passenger carryings saw the greatest growth, rising by 32.2% to more than 3 million while North American numbers rose by 14.7% to 733,000.
The weakest passenger growth was on Africa, Middle East and South Asia routes which increased by 1.3% to 475,000.
IAG traffic measured in revenue passenger kilometres increased by 11.9%.