“at risk” means that the flights are not under a Capacity Purchase Agreement by United.
For a normal Skywest flight that is operated under a CPA (for example SFO-SMF or ORD-ASE), United pays SkyWest a fixed amount to operate the flight and United prices the flight and collects all the revenue. In an “at risk” flight, United gives no money to SkyWest to operate the flight, but SkyWest gets to keep all the revenue for passengers that are flying nonstop on that flight, and a portion of the revenue for passengers connecting to or from that flight to a United mainline or CPA United Express flight. Skywest also sets the prices for these nonstops and has influence in the pricing of many of the connections using these flights.
Examples of Skywest at risk flights are LAX-IPL/IYK/SGU/YUM, SFO-CIC/CEC/OTH/, PDX-EUG/RDM/SEA, ORD-PAH/EAU/MKG/CMX, LAS-PSP/FAT, SMF-ACV, DEN-RKS/CPR and others. Many of these are subsidized essential air service flights.
Skywest can terminate these flights without the permission of United and/or change the schedule in any way as long as the United gates that handle them are available.
All of the Skywest E-120 flying under the DL code out of SLC is done “at risk”.
Another notable Skywest “at risk” operation was their FL coded flights out of MKE a few years ago.