With the airplane
The airport of Amleria is only at 30' minutes driving.
From Belgium (Zaventem and Charleroi) Ryanair proposes some cheap flights sometimes.
Take also a look at Jetair and Thomas Cook
Other airports :
MURCIA +/- 250 Km
MALAGA +/- 250 Km
With a rental car you must count 2,5 hours tot get to Tabernas.