In what situation might a passenger with a disability be denied boarding?

A passenger with a disability may be denied boarding if they pose a direct threat to the health or safety of others. This criterion is grounded in the fundamental principle that airlines must ensure the safety and security of all passengers and crew members. When evaluating whether someone poses such a threat, the airline must consider credible evidence and assess the individual's behavior and history.

In this context, a direct threat is defined by the airline's ability to demonstrate that there is a significant risk of harm that cannot be mitigated with reasonable accommodations. This may include situations where a passenger's condition could lead to sudden medical emergencies or aggressive behavior that endangers others.

While other scenarios provided can create complications, they do not inherently justify denial of boarding in the same way as posing a direct risk to health and safety. For instance, overbooking is a common airline practice that affects all travelers equally and doesn't rely on an individual passenger's actions or condition. Similarly, non-compliance with rules like identification requirements or causing disturbances might lead to other forms of resolution or mitigation, rather than outright denial.