Hi all -- I'm looking at a round-trip LAX-MAD in Premium Economy for this coming September. On my preferred return date of Sat 27 September the price differential vs any of the other days is significant (3x) and I'm wondering if anyone here has any more insight as to why this might be the case, or if I could expect it to change.

The outbound flight is IB 352 (LAX-MAD) on Sat 13 Sept. The fare for this leg is currently pricing out at $1118 for "Flexible" as part of a round-trip LAX<>MAD search.

But on the return MAD-LAX flight IB 351 two weeks later, the pricing for the return leg on Saturday, and just on Saturday, is 3x (!) the pricing on any of the surrounding days:

• Thu 25 Sep: $1091
• Fri 26 Sep: $1191
• Sat 27 Sep: $3595 -- I also noticed there is no "Optima" option on this day, and only on this day. Only a "Flexible" fare is available
• Sun 28 Sep: $1191
• Mon 29 Sep: $1191

Is this to be expected? I know that day-to-day differences are to be expected and a difference of several hundred dollars wouldn't be surprising to me. But a differential of +$2,400 for one day in particular seems crazy to me! It doesn't look like I've missed any Spanish (or American) holidays, but wondering if there's something else going on here.