Utilize the input text as a context reference, choose the right relationship between Lufthansa and Brussels Airlines from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

The strike only affects Lufthansa services, while flights by its subsidiaries -- Germanwings, Swiss, Austrian Airlines and Brussels Airlines -- are operating normally.

Answer: subsidiary