This is an email I received today from Spirit. It will answer your question...
Subject Line: Your Travel Plans have been cancelled
Reservation date: 13Jan2005
Spirit Airlines regrets to announce that we are discontinuing service between Chicago and Orlando effective January 9, 2006. Record high fuel prices have substantially impacted Spirit's ability to operate on this route profitably.
Spirit must take this action as part of its plan to continue to offer low cost flights throughout North America and the Caribbean during these difficult times for the airline industry.
We truly apologize for this inconvenience. We invite you to make changes to your travel plans. You may change your destination without paying a change fee or difference in fare if you travel on the same or within a day of your original travel dates. Outside of those dates fare difference will apply. If you are not sure of your plans, you may place your reservation on hold for future travel to be booked and completed by one year from the original date of purchase or you may contact us to receive a refund.
For assistance you may contact the Spirit Airlines Reservation Center by calling toll free 800-772-7117 or en Espanol al 800-756-7117.
We are flying with them, next month, out of Atlantic City. After my initial panic, from reading the first line, I continued reading. I called Spirit and was told they made a mistake sending me this email, duh, and our flights are fine.