I can’t speak for the USA in first , however I do follow the London Malaga availbilty as I travel there frequently.

This is changes all the time. I am going this Sunday and I booked a paid for ticket as nothing was available

Since booking I have Done a daily reward search. It has ranged from an early flight , no flights and an afternoon flight ( this mornings search ) so it changes quite a bit.

The other week week there was nothing. On Sunday morning I searched at 10:30am. Flight from London city. Was airbourne at 1pm

i dont have have to go , and can go at nil notice so it works for me most of the time unless I chicken out and buy a revenue fare like this week.