Good advice. Also, look for non-stop flights anywhere east of the Mississippi that flies into Orlando. It doesn't necessarily have to be a Delta hub. You might be able to fly into the non-hub city, then fly into Orlando. If you have a passport, you're not even limited to flights in and out of the US. You might luck into a transfer in Toronto or Nassau. Anything can happen.
Once, I was flying out of Los Angeles as a non-rev (free airfare; my daughter used to work for Delta). At the last minute, the flight I wante to take filled up with paying customers, and I had to wait until the next flight in 12 hours. However, if I had my passport with me, I could have flown from Los Angeles into Guadalajara, Mexico and transfered planes there. Unfortunately, no passport, so I didn't get home until mid-day the next day.
Good luck. Hope you make WDW with little or no delay.