Frontier Airlines EarlyReturns - Frontier in Santa Barbara?

I was at the gym around 5 pm +/- 1 hour yesterday and I saw a Frontier plane (regional jet?) taking off from SBA.

After thinking about it, is somehow a Horizon flight to Portland or Seattle?

Frontier is gradually transitioning from Horizon Air to Republic Airlines as their express carrier and as a result, some Frontier JetExpress aircraft have been returned to the Horizon system but have not been repainted yet.

So yes, you probably saw a QX flight departing! :)