SFO to Spain

Depending on when the trip is, skyscanner.com shows there are one stop options for SFO-XRY ( Jerez)

Use skyscanner for research, but buy directly form the airline

While you can certainly find one stop options to Jerez, it is a small airport and the options will be limited. You can also look at flying to Seville, a much larger airport only 80 km away.

You’ll may need to fly into Madrid then on the Jerez. As Balso stated, there are limited flights into Jerez. Iberia has two daily flights; one morning (07:30) and one afternoon (15:30)/evening (19:30). There are four daily Iberia flights from Madrid into Sevilla. I can’t speak to the SFO part, but from Washington DC, flights arrive in Madrid at 05:55 so catching the morning flight isn’t an issue and we have done so in the past. Jerez’s airport is very small and only a few minutes outside of town. Due to its location northeast of town, the airport in Sevilla is probably about a 1.25 hours drive from Jerez, but an easy drive.

I picked a random date in September and saw that United has a flight from SFO to Frankfurt (UA926) then on to Jerez ((LH4408), but it may be a seasonal flight and not always available since it wasn’t on the schedule for May. Everything else I saw had 2 stops. You might also want to check connections through Lisbon.

Have you tried Google Flights? Do you mind arriving at Seville?

The cheapest airline from SFO is Level, they fly direct to BCN Barcelona, then a short hop to Jerez. There are no direct flights from the USA to Jerez which is a small town like Modesto. I'm not recommending Level, just letting you know they are cheap. From LAX you can get to MAD Madrid directly using Iberia, also not recommending them either. I prefer American, most flights will route you thru Texas or British Airways which will always routes you thru London. If you use BA make sure you London connection is in-and-out of Heathrow not one of the many other airports in London. Best Regards J