The London-listed budget airline, which is looking to grow market share and last month acquired take-off slots at Gatwick from rival Norwegian, had slashed ticket prices in a bid to fill flights over winter.
Today the Hungarian carrier said its planes had a load factor of 75.4% last month, compared with 56.1% in December 2020.
Bosses also told investors that from March it will raise the number of aircraft based at Gatwick from one to five, opening up new routes from the London airport to 14 destinations including Faro, Palma, and Mykonos.
As part of environmental rules, Wizz Air also revealed its CO2 emissions levels, with 277,000 tonnes emitted during the month, although this was down per passenger from 85.6 grams per kilometre to 63.8 grams per kilometre.
The airline saw shares surge as much as 9.6%, or 403p, to 4591p this morning.