I am shopping for a carry on for a trip to Spain, flying Delta and Iberia. Most brands divide them into domestic and international size, with international being slightly smaller. It is my understanding that international size typically applies to flights originating outside US and not to those going from US abroad. Following that logic, I was expecting that Iberia would require something smaller that Delta. I am finding however that Delta's limit is 22" x 14" x 9" (or 56 x 35 x 23 cm) while Iberia's limit is actually higher, 56 X 45 x 25 cm.
I wonder whether this is accurate. Because I need to buy a bag, I want to make sure what I am buying would work. Has anyone had any issues with a 22"-wide bag on either Delta or Iberia?