What is the relationship between Avianca Holdings and airline in the context of the input sentence. Choose an answer from: 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