Wizz Air Holdings PLC (AIM:WIZZ), the European airline, revealed its CO2 emissions increased in June despite passenger numbers remaining relatively flat year-on-year.
Some 5.78 million seats were purchased last month, marking a 0.4% rise compared to 2023, with total passengers dropping by 0.2% to a little over 5.3 million.
However, CO2 emissions per passenger/km, which excludes cargo flights, saw a 4.2% lift to 53.6 from 51.5 a year prior.
Wizz Air said the emission increase was because it was keeping hold of older planes and "the wet lease of smaller gauge aircraft" which it uses to maintain its network footprint while other models are grounded for GTF engine inspections.
The airline also warned that its manufacturing output needed revising as, although its long-term growth forecasts remain unchanged, it is expecting disruptions to its ongoing fleet plan for the next couple of years.
Last month, the budget airline was found to be the biggest offender for delaying its flights in the UK.
On average, flights from the budget airline leaving the UK depart 31 minutes and 36 seconds after they are scheduled to, research from the Civil Aviation Authority found.
While it is a slight improvement on last year, it wasn't enough to stop Wizz Air from being crowned the tardiest airline for the third consecutive year.