Germany is considering issuing financial aid to the Condor airline after Thomas Cook declared bankruptcy.
Thomas Cook, which has a 49% share in the airline, collapsed on Monday.
Condor has applied for a bridging loan from the federal government and is awaiting a response, with German media reporting the amount requested was €200m ($220m; £176m).
Thomas Cook's collapse has reportedly left 600,000 tourists stranded, including tens of thousands of Germans.
German Economy Minister Peter Altmaier said that the government would make a decision on financial aid within the coming days.
The government in the state of Hesse has already promised its support, a statement from the airline said.
"I assure you that we will do everything in our power and leave no stone unturned, so that our fleet continues to bring our guests reliably to their holiday destinations all over the world and back home as usual," Ralf Teckentrup, chairman of Condor, said.
Condor has said it will not carry passengers who have booked with Thomas Cook or its subsidiaries. Those passengers have been advised to get in contact with their tour operator.
A German government official said that compulsory insurance should cover most German travellers if they were stranded abroad, Reuters reports.
What has happened to Thomas Cook in Europe?
Thomas Cook's subsidiary in Germany is still operating but has stopped taking bookings, DW.com says. This includes all of its German subsidiaries such as Neckermann, Öger Tours, Air Marin and Bucher Reisen.
Thomas Cook's German operations are widely considered to be in a healthier state and have remained profitable, DW adds.
The Dutch unit of Thomas Cook has cancelled all travel booked through Thomas Cook Netherlands and subsidiary Neckermann. The companies said that they looked into the possibility of fulfilling the booked journeys but were unsuccessful. A special call centre has been set up for those affected.
Currently, there are 10,000 Dutch tourists abroad with Thomas Cook.
In Belgium, Thomas Cook's unit there says customers who have booked a package holiday cannot travel for the time being. A number of Thomas Cook Belgium's offices were closed on Tuesday.
Leen Segers, spokeswoman for Thomas Cook Belgium said: "We decided not to let any new customers leave today. We are looking for solutions for Thomas Cook Belgium. We want clarity before the customers leave again."
Brussels Airlines has also stopped accepting passengers who have booked a package through Thomas Cook and Neckermann. The Belgian airline also said on Monday that it would start cancelling flights that it operates on behalf of Thomas Cook. Two flights from Brussels to Tunisia were cancelled on Wednesday.
How have businesses around the world been affected?
There is concern in countries such as Egypt and Greece that local businesses could be financially impacted by loss of tourism.
- The Gambia's government has held an emergency meeting over the collapse of Thomas Cook. There is concern that its collapse will heavily impact tourism which contributes more than 30% of the Gambia's GDP
- In Egypt, Thomas Cook operator Blue Sky said reservations until April 2020 have been cancelled. Bassem Halaka, chairman of the Tourism Syndicate in Egypt, said that Thomas Cook "was a major organiser of charter flights from the UK to Sharm El-Sheikh" and that tourism in these resorts would be affected
- In Cyprus, the loss for hoteliers and the wider economy is about €50 million, according to Cyprus' deputy tourism minister Savvas Perdios. He added that hotels were owed money for July, August and even September
- 50,000 tourists are stranded in Greece, according to the tourism minister. Grigoris Tassios told local TV that hotels were expected to make losses on payments from the past two months. He said that hotel companies would attempt to recover money from Thomas Cook in court
- In India, Goa's Travel and Tourism Association said that the loss of Thomas Cook is a "big, big, blow to the industry."
- Spain's Balearic Islands faces million of euros in losses. Thomas Cook has a tax office in Palma with hundreds of employees, and also works with 20 hotels in the Balearic Islands and 20 in the Canary Islands
- About 53,000 British tourists in Spain have been affected. Spain's ministry of tourism has been in contact with German and Swedish authorities to ensure their subsidiaries will continue to operate during the winter season.
- Turkey's Hoteliers Federation (TUROFED) has warned that the country could miss out on up to 700,000 tourists a year due to the collapse of the tour operator. The chairman of TUROFED, Osman Ayik, told Reuters: "There are a large number of small businesses whose fates depend on Thomas Cook, especially in Mugla, Dalaman and Fethiye." He added that some small hotels in Turkey are still owed around £100,000 - £200,000 ($125,000-$250,000)