From many city around europe you have some great flight Connexxion to Lake Garda.

If you land at Milan Bergamo. Take the bus Autostradale to Brescia. http://www.autostradale.it/pdf/nuoviorari/BGY-%20BRESCIA%20W14.pdf

You will arrive at the big bus station, walk 5 min and you are at the small bus station.

From there you take the next bus or busses to Limone sul Garda. Plan your route here: http://www.arriva.it/web/guest/results/-/search?q=limone+sul+garda+brescia&redirecting=true&freesearch=true

Warning do not plan your route with google maps. Often google maps uses not up to date bus times.

From Verona airport you can use google maps to plan your travel to Limone sul Garda or to Malcesine. In Malcesine you can take the ferry across to Limone.