I was curious if it was illegal as well but after looking into it

"Certain entities are except from the restrictions of the Telemarketing Sales Rule (aka “TSR,” “the Rule” or “the Do Not Call list”), the restrictions on prerecorded calls, or both. These include certain prerecorded healthcare messages and some prerecorded messages placed on behalf of a non-profit charitable organization to previous donors. A blanket exemption is held by political organizations, telephone surveyors, and companies that have an existing business relationship with the recipient."

I'm guessing applying for their airline once 4 years ago must be their rationale