Monarch is looking to cut up to 1,000 jobs – a third of its workforce – as it plans to compete with low cost airlines Ryanair and EasyJet.
The private company, which is currently controlled by the Swiss-Italian Mantegazza family, is undergoing a strategic review of its business in a bid to attract new investors.
Monarch Airlines confirmed last week that it will end all charter flying at the end of the winter and operate only scheduled flights from next April.
The Financial Times reports its fleet will reduce from 42 to 30 aircraft.
It says Monarch will retain its focus on holiday destinations such as Spain, the Canary Islands and Turkey but add more European cities and skiing destinations. Overall, it will fly more frequently to fewer destinations.
New chief executive Andrew Swaffield, who was previously at International Airlines Group before joining Monarch in April, is leading the review.
Monarch said in a statement: "The company has previously stated that the new management team is conducting a strategic review of the group’s businesses, including in relation to their operations, ownership and financing.
"That review is ongoing and further announcements will be made upon its conclusion or as otherwise appropriate."
