I am trying to use my AMEX companion ticket for a trip to MCO in March. There are currently no fares that meet the L U T availability. I'm about ready to just purchase tickets on Sun Country as they are half the price (and non stop).

Question: As we get closer to this high season flight will seats most likely open up? Or should I buy my cheaper alternative now, while it exists.

If it matters I am a Plat, soon to be Diamond. Thanks!!