Rent a car
Make sure to pre book your hire car before flying in to Gibraltar. This is very important specially during the summer months when there can be shortage of hire cars at most companies. There are several rental car companies in La Linea serving Gibraltar customers and travelers. The advantage with getting the car in La Linea is to avoid waiting time at the border. Walk across and avoid any delays crossing with a car. Some companies are based diectly on the Spanish side with the cars in one of the underground garages close by, just a few minutes walk from the flight terminal in Gib.
Most important is to find a hire car company with inclusive rates. Pay what you were quoted online and avoid additional costs on arrival by doing price checks before you arrive.
On our Gibraltar airport car hire page on this site we have much useful information for when booking a car for Gibraltar. Check out http://brunoscar.com/locations/gibraltar-airport-car-hire