Utilize the input text as a context reference, choose the right relationship between Avianca Holdings and airline 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.

In addition, while three ASUR's main airline customers at Mexico, Avianca Holdings and LATAM Airlines Group, recently filed for Chapter 11 bankruptcy protection in the United States.

Answer: industry