LONDON — One day after the British tour operator and airline Thomas Cook abruptly collapsed, leaving hundreds of thousands of travelers scrambling to make arrangements, the head of the Civil Aviation Authority in Britain promised that “nobody” from her country would be stranded and that subsidiaries in several countries were working to bring people home.

Thomas Cook said on Friday that about 600,000 people were traveling abroad on its services, raising the prospect of hundreds of thousands of travelers stranded overseas after the company collapsed in spectacular fashion, but initial reports suggested that governments and private companies were moving to bring people home.

In addition to the vast repatriation effort in Britain, several companies that were either subsidiaries of Thomas Cook or that use the name while running independently were still operating in China, France, Germany and India.

But shortly after midday on Tuesday, Thomas Cook’s subsidiary in the Netherlands, which on Monday said it was open for business as usual, reversed course and said it had filed for insolvency. The Thomas Cook subsidiary in Belgium said on Tuesday that it remained operational, for now, but added that it was declaring partial bankruptcy and had laid off 75 employees.