The Wizz Air flew 1.56m of passengers last month, down 20% since August.
As quarantine rules are affecting airlines, Wizz Air reported a 60% decrease in passengers compared to previous September.
The airline flew about 4 million passengers in September 2019, compared to 1.56 million in September 2020.
Despite the new quarantine rules, the airline said it continues to expand across Europe.
Other airlines also feel the impact of the pandemic and limited travel.
Ryanair flew 5.1 million passengers in September, compared to the same period a year ago.
An airline spokesman said: “However, because customer trust is eroded by the government’s noncontrolling rules of community travel policy, many Ryanair customers are unable to travel for business or emergency family reasons without being exposed to 14-day quarantine.”
The airline is asking the government to change current quarantine rules and introduce airport testing.
