Jerez de la Frontera airport has daily domestic flights from Madrid and Barcelona and weekly flights to/from London, Düsseldorf and Frankfurt. From Jerez airport you will need to take a taxi to your hotel or conference venue and the cheapest option is to take the local train from the airport to Jerez train station. Check the timetable as there are few train connections and they do not always coincide with flight arrivals.
You can also fly into Seville airport, an airport with numerous international connections, from Seville, take a train to Jerez de la Frontera.