Hi, thanks for the question. We bought our bags from Costco and Amazon. The Amazon version is here Amazon Basics Underseat Carry-On Rolling Travel Luggage Bag, 14 Inches, Navy Blue a.co/d/e7160KO. Generally we will advise to be careful with taking a rolling suitcase even if it meets the measurement but the bottom is hard or the wheels may exceed the measurement, it may not fit in the carryon bag check slots when boarding a plane. We have switched to mostly backpack since they are made of soft materials and if needed they easily can pass a test.
Those flights suck it's the worst seat in the world your knees about to pump into the front seat I just came back from South America on that flight that's the worst
Mostly because it's cost effective. What I find interesting is that I can never find a flight on their 787-8. You can find more about their fleet here www.avianca.com/en/about-us/our-fleet/ en.m.wikipedia.org/wiki/Avianca
Yes they do ensure you are following guidelines. We made sure our baggage will Fit inside the luggage size. You can check the size limits here www.avianca.com/en/information-and-help/baggage/