By Chris Isidore, CNN Business

Delta is in danger of defaulting on some of its debt -- not because it doesn't have enough cash, but because it expects it cannot comply with the current terms of its borrowing.

The airline said in a filing Wednesday that it negotiating with lenders to change those terms. But it cautioned that "based on the reduction in demand that we have experienced and are continuing to experience as a result of the Covid-19 pandemic, we expect that we will not be able to satisfy," some of those existing terms by early next year.

The loan term in question involves the company's "fixed charge coverage ratio," a measure of its ability to pay fixed expenses, such as aircraft leases, airport rents and other fixed costs, including debt payments, rather than variable expenses such as salaries, benefits and fuel costs. The company's ratio could be too low to comply with the current language in the debt agreements, even if it has the cash to make the payment.

Delta's predicament is an indication of how the crisis can hurt a company that is relatively flush with cash. Delta said in the filing that it should have $14 billion in cash available at the end of June and $10 billion in cash available at the end of 2020. It is preparing to sell more debt in the public markets to build up those cash reserves.

Delta also said in the filing that it expects second quarter revenue to fall 90% from a year ago, but that cost cutting efforts should mitigate its daily cash burn to $40 million by the end of June, compared to $100 million at the end of March.

The default warning in the filing is a sign of the cash squeeze companies are facing during the current crisis, particularly in the airline industry, where traffic more than 80% lower from year-ago levels despite a modest rebound at the start of the summer travel season.

Shares of Delta fell nearly 10% in late morning trading Wednesday, but most US airline stocks were down even further after a note from JPMorgan airline analyst Jamie Baker suggested that a recent rally in airline stocks lifted share prices too high and that trouble lies ahead once the summer travel season ends.