Southwest Airlines, American Airlines, Delta Air Lines, United Airlines, Alaska Airlines, and JetBlue experienced issues with their computing systems leading to flight cancellations and delays throughout April 1. Third-party contractor Aerodata is a company which offers aircraft performance data, weight and balance data, and load planning services to the airline industry to support approximately 21,000 flights per day. Just five minutes of system downtime can result in over 100 delayed flights and loss of revenue, according to a customer case study issued by VMware.
Source: https://www.bleepingcomputer.com/news/technology/us-airlines-cancel-delay-flights-because-of-aerodata-outage/