Yes, the flights are cheap on Memorial Day. This is because the airlines offer special discounts on these days to fill the seats quickly. However, there is competition between the aircarriers to fill the seats quickly, so they give discounts to attract a large number of passengers. However, to grab the benefits of Cheap Flights Memorial Day Weekend deals, one has to book their tickets well in advance because during this time, a large number of passengers book flights for holidays. So there might be a chance that the ticket gets booked quickly.