A number of airlines have expressed interest in taking over Flybmi's City of Derry to Stansted service, the airport's operator has said.
Scottish airline Loganair has already indicated an intent to tender for the publicly financed route vacated by Flybmi after its collapse.
The demise of Flybmi is the latest blow to Northern Ireland's troubled third airport in Derry. It is owned by the local council and run by Regional and City Airports.
Clive Coleman, the contracts director at Regional and City Airports, said it would be "challenging" to run the airport without the Stansted flight.
"A number of airlines contacted us saying they were interested. We are in discussions with a number of them now and we've been working with the Department for Transport on that," he said.
Fears for Derry Airport's future as Flybmi goes into administration pic.twitter.com/c3FYj0xthR— RTÉ Business (@RTEbusiness) February 18, 2019
Mr Coleman declined to indicate how many airlines were vying to take over the service, which is supported by UK government funding through a public service obligation (PSO).
The subsidy, which has been in place since 2017, was the first of its kind in Northern Ireland.
Last week, UK Transport Secretary Chris Grayling confirmed the government will continue to provide the PSO funding until 2021.
Derry City and Strabane District Council has said it is "committed" to securing an immediate replacement airline for the route.
It engaged in emergency talks with the airport and Department of Transport over the weekend.
Flybmi operated two return flights a day from City of Derry to Stansted from Sunday to Friday, and one return flight on Saturdays.
British Midland Regional Limited, which had operated 17 regional jet aircraft on routes to 25 European cities, cancelled all flights from Saturday.
Loganair and Ryanair are now the only airlines serving City of Derry airport.
On Sunday, Loganair confirmed it has expressed an interest in the Flybmi route, with a spokesman saying the airline has an "extensive track record as a public service obligation (PSO) provider and knowledge of the Derry market given they already operate to Derry from Glasgow".
In 2016, the Northern Ireland Executive pledged £7m to the loss-making airport, stressing the need to maintain air connectivity from the north-west of the region.
Meanwhile, most of flybmi's 376 employees have lost their jobs following the airline's collapse, the administrators have announced.
British Midland Regional Limited, which operated as flybmi, employed a total of 376 employees based in the UK, Germany, Sweden and Belgium.