"Air" is where you set it when you are scanning for channels using the antenna. When you are hooked to cable you need to change it to "cable" and then scan.
The only real problem I've had with the Seikis in my 2015 Vegas is at Disney Fort Wilderness. Their cable system is encoded and without a QAM tuner in the Seiki, they will not find channels. In our bedroom there is a Sakyo instead of a Seiki and that TV has a QAM. So when we are at Disney we just watch TV on that one in the bedroom because it will scan QAM coded channels.
We don't really watch a lot of TV -- generally just when we hit the beds in the back and the Sakyo works just fine. We are too frugal to replace the Seikis while they work fine on un-encoded cable systems and antenna.
And don't forget -- turn off that antenna booster when you are on cable because it will inhibit the cable reception.
Ed & Bev Felker
Retired USAF Col and retired Nurse
Traveling with Lily & Bella ('Teddy Bear' breed)
2015 Vegas 24.1 (E-350)