Callie Kimball and her husband said that they and their son, Carter, were removed from a Spirit Airlines flight from Las Vegas to their home city of Little Rock on Monday morning, despite showing staff a doctor’s note stating that he’s exempt from wearing a face-covering.

According to his parents, Carter “holds his breath” or “starts freaking out” and “will harm himself” whenever he wears a face mask.

Spirit Airlines, which is attracting widespread criticism for the incident on social media, said that its current face mask policy “does not provide for medical exemptions, regardless of diagnosis,” but that it plans to introduce an exemption application process for customers with “a medical disability” later this week.

The company has also issued a refund to the Kimball family.

“Regardless of local or state ordinances federal law requires all travelers to wear face-coverings in compliance with CDC guidelines on flights and in airports,” Spirit Airlines’ COVID-19 Information Center currently states.

“Children under the age of 2 years old are exempt. We will continue to evaluate this policy as the situation evolves.”

However, the Centers for Disease Control and Prevention’s (CDC) mask guidelines explain that people “with a disability who cannot wear a mask, or cannot safely wear a mask, for reasons related to the disability,” are also exempt from the requirement to wear a face mask.

In September, Spirit Airlines staff asked the parents of a 4-year-old boy with autism to leave a plane because their son wouldn’t wear a face mask.

When they refused, Spirit Airlines ordered all passengers off the plane and called the police. The parents were subsequently banned from flying with the airline.

“Spirit is aware of and analyzing a new federal directive regarding a requirement for masks to be worn in airports and onboard flights. We will promptly share any information regarding exemptions or policy changes,” the section reads.

“At this time, our current policy still stands that all guests, except children under the age of 2 years old, are required to wear an appropriate face-covering.”

Spirit Airlines says that it reminds customers of its face-covering policy “throughout the booking process, in a pre-trip email sent prior to departure, and in a required acknowledgment that is part of the check-in procedure.”

However, in response to the incident involving Callie Kimball, the company has said that from Friday customers who are due to fly with Spirit Airlines from Monday will be able to “apply for an exemption as provided for in the federal mandate requiring masks in airports and on planes.”

A Spirit Airlines spokesperson told Newsweek in a statement via email: “We sympathize with families facing additional burdens while traveling, including those dealing with medical conditions. Like most airlines, Spirit Airlines started requiring face coverings in May 2020 with the only exemption being one for children under age 2.

“We remind Guests of our face covering policy throughout the booking process, in a pre-trip email sent prior to departure, and in a required acknowledgement that is part of the check-in procedure. Our existing policy does not provide for medical exemptions, regardless of diagnosis.

“Starting March 19, 2021, Guests with a medical disability who are traveling on or after March 22, 2021 can apply for an exemption as provided for in the federal mandate requiring masks in airports and on planes.

“We plan to add information to our website about the exemption later this week. Please visit our Information Center for more information on what we are doing to keep our Guests and Team Members safe.”

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Update 3/16/21, 11 a.m. ET: This article was updated with comment from Spirit Airlines.