This is from
Delta's form 8K:
Item 2.06 Material Impairments. Delta has decided to retire the company’s Boeing 717-200 aircraft and the remainder of its 767-300ER aircraft by December 2025 and its CRJ-200 aircraft by December 2023, earlier than previously scheduled. These plans are another step in Delta’s fleet simplification strategy, which is intended to streamline and modernize Delta’s fleet, enhance the customer experience, and generate cost savings. As a result of this determination, Delta evaluated its Boeing 717-200 and CRJ-200 aircraft as well as the remainder of its Boeing 767-300ER aircraft for impairment and, on September 23, 2020, concluded that the carrying value of these aircraft was no longer recoverable when compared to their estimated remaining future cash flows. Consequently, during the September 2020 quarter, Delta expects to record non-cash impairment charges associated with these aircraft. Although the actual amount of the charges has not yet been finalized, Delta expects the aggregate impairment and other related charges to be in a range from $2.0 billion and $2.5 billion, before tax. An immaterial amount associated with the charges is expected to result in future cash expenditures. Delta may continue to consider further opportunities for early aircraft retirements in an effort to modernize and simplify its fleet.