I noticed that certain dates on Delta! departing from NYC and arriving in MIA are 7.5k miles each way
Tons of dates in Jan, Feb, March
the dates I noticed are
NYC-MIA
January 5th - 13th 19,20,21,23-27th
February 7, 8, 9, 10, 16, 17, 19, 22 23 24
March 8th and 9th
MIA-NYC
Jan 7,8, 9, 11, 12,13,14,19,20,21,22,23,25,26,27,28,29,30,31
February 1, 2, 3, 4, 5...
March 15th 16th 17th
among many others!