Wizz Air Holdings Plc (LON:WIZZ) said it expects to operate at 60% capacity in the second and third quarters of the financial year.
The low-cost carrier initially estimated to work at 80% capacity in its third quarter, which ends in December.
READ: Airlines flying higher as easyJet, Ryanair and Wizz Air increase summer capacity
The new forecast is based on renewed travel restrictions imposed across Europe and in Hungary in particular.
If further capacity cuts are needed, the airline is considering to park parts of its fleet throughout the winter season to protect its cash balance.
Shares slid 6% to 3,644p early on Tuesday.