I read on https://www.yahoo.com/news/airline-cancels-flights-shuts-down-150059412.html:
All credit card purchases should be refundable through your credit card company or your travel agency.
tickets not purchased by credit card will still be eligible for refunds, but those would-be passengers will have to get in line with other airline creditors.
Why do customers who used their credit cards have "refund priority" over customers who didn't in case of a bankruptcy?