(Sharecast News) - Budget airline Wizz Air said capacity numbers were held back in June by the ongoing impact of groundings of Pratt & Whitney GTF engines, while CO2 emissions increased as it was forced to use older planes.

Capacity as measured by the total number of seats increased by just 0.4% on last year to 5.79m, however the load factor - a measure of how full planes are - decreased to 91.7% from 92.2% last June.

Passenger numbers meanwhile decreased by 0.2% year-on-year to 5.31m, which the company said reflected "a focus on overall revenue management".

Nevertheless, rolling 12-month passenger numbers were 14.7% higher at 62.10m while the 12-month load factor improved 0.6 percentage points to 90.1%.

Wizz said in May it expects to have around 50 aircraft with GTF engines grounded awaiting engine inspections by the end of the first half of the financial year, marking year since the first aircraft was grounded in September 2023.

The month of June saw a 4.2% year-on-year increase in CO2 grams for each passenger kilometre travelled to 53.6g.

"This reflected the retention of older planes and the wet lease of smaller gauge aircraft to maintain Wizz's network footprint while aircraft are grounded due to GTF engine inspections," the company said.

Shares were down nearly 1% at 2,131.2p in early deals on Tuesday.