Avianca has today (3/4/20) begun selling basic economy style fares on flights to and from the United States. They are marketing their flights in “sizes” from Extra-Small ro XXL, which will indicate how much is included in your fare.
Obviously the “smaller” the fare, the fewer inclusions (and in some cases the more you’ll pay to add those things later). While I’m sure there are some folks who will be happy to travel light and save a bundle, I expect that most people will want the additional comforts that were long standard in economy class, including a checked bag seat selection, etc. I’m sure that Avianca is also banking on customers to want those things and be willing to pay for them.
In some cases, how much more you’ll pay could be pretty significant. For example, for a flight between North America and South America will set you back $44.99 for seat selection on an XS fare (versus $24.00 with an “S” fare or $24.99 with an “M” fare.
Furthermore, mileage accumulation will be lower with cheaper fares with as few as 10% of mileage flown awarded (which will likely also be reflected in partner earning, though it’s always worth checking wheretocredit.com).
Overall, this is a net negative for those booking paid fares. To my knowledge, awards will still book into a fare class that includes seat selection and a checked bag and full-size carry-on, but it’ll be worth keeping an eye on it to monitor whether they also offer a stripped-down option from an award perspective.