American travellers preparing for the busy Thanksgiving travel rush received a rude surprise in their inboxes last week.
"There has been a change to your upcoming flight" read the foreboding subject line.
The email that was received by thousands of passengers with Frontier Airlines directed them to call the airline's "rebooking hotline" to discuss next steps.
Within minutes the call centre was in gridlock under the weight of incoming calls from travellers, concerned about their holiday plans. Some passengers reported being forwarded straight to voicemail.
The customer assistance Twitter account didn't fare any better, which was immediately swamped by anxious tweets. "Can we get an update as to what is going on with these emails cancelling flights?" wrote one concerned traveller who called the emails "very unprofessional."