Alaska Airlines is a good option to consider as they have direct flights from Los Angeles, CA to Loreto.
AeroCalifornia and AeroMexico have flights to Loreto for around $350 - $450 round trip depending on scheduling and ticket payment. Please contact AeroCalifornia 800-237-6225; or AeroMexico 800-237-6639 for more information. Please allow 2 ½ - 3 hours between connections as you will be checked through customs on your return.
Several airlines have flights to La Paz and Los Cabos leaving from the west coast or the southwest. It is then 2 hours from Los Cabos to La Paz and 4 ½ hours to Loreto by bus (or catch the a.m. flight La Paz-Loreto on Aero Litoral a branch of AeroMexico). Please call us if you are having difficulty securing flights to Baja.