At the time of writing, the following carriers fly into the 2 airports that are local to Torrevieja:

Departure AirportArrival AirportCarrierFrequencyPeriod
EdinburghAlicanteAirScotlandSat & TuesAll year
EdinburghAlicanteFlyglobespanDailyAll year
EdinburghMurcia FlyglobespanDaily
EdinburghMurciaJet2Various Days1/4 - 28/10
GlasgowAlicanteAir ScotlandSat & TuesAll year
GlasgowAlicanteEasyjetDaily7/7 - 28/10
GlasgowAlicante FlyglobespanDailyAll year
PrestwickMurciaRyanAirFri, Sun & Mon

Two very useful flight comparison sites are Skyscanner and Weefly.