United Airlines on its website has been offering low, refundable fares to compete against rival carriers. If you know where to look, you can find them in global distribution systems, too.
The only way to access "economy flexible" fares in a GDS is by using a special code in the "passenger type" field. That means typical low-fare searches don't turn up the fares and corporate online booking tools generally don't have them.
Sources guessed United created the competitive but refundable fares to fend off the likes of JetBlue and Southwest. United's economy flexible is on the . . .