This article intended to find out and summarize the changes that American airline companies (Delta as a target) have to undertake in this unprecedented pandemic. Based on accurate statistics of 2020, this paper studies the industry overview mainly from three aspects-cost, revenue, and other issues. The Manpower field operation and the maintenance cost decreased and hedge strategies adjusted sharply during the COVID. In the Revenue part, the authors investigated that from the passenger airlines and the cargo airlines. We also made researches on the performance of stocks, policy regulations, and requirements. As is shown, though the COVID is a devastating impact on many industries, especially on the airline, there is still some good news readers can see from the statistics like derivative hedges, cargo performance, and policy support. This article is not only a review of historical data but also a precaution to the airline industry for those unintended financial catastrophes. This article hopes that not only the U.S. aviation industry, but also the global aviation industry need to pay attention to this type of event. Such incidents will directly affect the normal operation of airlines. Airlines need to reserve multiple plans even to deal with future emergency measures in order to avoid various company-related problems.