Bookable on Expedia, or Kayak.
Tickets booked are refundable for 24 hours.

From JFK to MIA:

From $49

July 16, 17, 30
August 20, 21, 26, 27, 28

From $59

September 1, 3, 4, 5, 6, 10, 11, 17, 18, 24
October 29, 30
November 5, 6, 12, 13, 19, 20
December 10

From $89

January 6, 14, 27, 28, 29, 30
February 1, 2, 3, 4, 5, 8, 9, 10, 11, 26
March 1, 3, 4, 5, 10, 11, 12, 17, 18, 19, 24, 25, 26, 31
April 1, 2, 7, 8, 9, 14, 15, 22, 23, 28, 29, 30
May 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 20

From MIA to JFK:

From $49

July 17, 25, 31
August 6, 7, 8, 13, 14

From $59

September 5, 6, 10, 11, 17, 18, 24, 25
October 1, 2, 8, 9, 29, 30, 31
November 1, 5, 6, 12, 13, 19, 20
December 4, 11, 17, 18

From $89

January 28, 29, 30, 31
February 1, 4, 5, 6, 7, 8, 11, 12, 13
March 5, 6, 7, 12, 13, 19, 26, 27
April 2, 3, 9, 10, 16, 23, 30
May 1, 7, 8