Well, technically you can’t, there is not an airport here. Yet. Most recent news says we may have an international airport in a few years. So that leaves basically three options to fly near enough in order to grab a shuttle. The options for flights comes down to a time vs. budget consideration. Plane tickets rise in price the closer you land to SMA. Closest to furthest are Queretaro, Leon, and Mexico City.
Queretaro Airport (QRO), a lovely town in its own right, is a little over an hour away. Problem for your budget is, flights cost about twice as much as to Mexico City. It’s close enough that you could take an actual taxi into San Miguel de Allende for about $25. Interestingly, the shuttle from QRO is $29 per passenger.
Sometimes you will find good prices for flights to Leon Airport (BJX) about 2 hours away with traffic. The same company above runs shared shuttles for $29 a person as well. Taxis may be slightly more.
Mexico City (MEX) is 3 ½ hours away, but there are often great prices for flights there. The above company offers a shuttle for $75 a person, 2 person minimum. Of course if you are flying into MEX to save pesos, you may want to look at Primera Plus bus line that has clean, comfortable buses – including your own internet screen! The one setback is with flight time and ground transpo time, you really are losing a day (another on the way back) of your trip. Our suggestion is to spend the night in DF, enjoy a museum and a great restaurant and leave for SMA early the next day. They will take you to Queretaro for about $20. There you can get another bus for about $8, or grab a taxi. Here is their English booking site: