In a comment provided to Quartz, United Airlines said that “most United flight attendants are going above and beyond for our customers this summer. However, this year we’ve seen the number of sick calls spike on weekends – and only weekends. Our contract with the Association of Flight Attendants allows the company to require a physician’s note in cases of suspected abuse of sick time. The policy is narrowly tailored to the days when abuse has been occurring, and we hope to return to our usual approach of not requiring a doctor’s note soon.”