Perpignan is a short 30 minutes drive away and is the closest airport. The flight time from London Stansted is around 90 minutes. Another good option is Gerona in Spain which is a slightly longer flight time and about 90 minutes drive. There are more flights to Gerona and they can be cheaper. Other airports in France such as Montpellier, Nimes and Carcasonneare are also within reasonable driving distances. Along with Perpignan, these are small provincial airports so collecting your luggage and car is quick and easy.
Ryanair are usually very competitive and give a good service and fly to all of the airports above from London Stansted and most from London Luton. Ryanair flights are usually cheap but they make their money by charging for luggage. Make sure you book your luggage when you book your flight as it will cost double if you add later, or at the airport!
Easyjet fly direct to Barcelona in Spain from both London Gatwick and London Stansted. Their prices are competitive but the drive from Barcelona takes about 2 hours. They are still worth a look as the flight timings can be good.
Car hire can be cheaper in Spain but you may have to pay additional insurance to bring the car into France so this needs to be taken into account.
auto-europe is a broker and they will find the best deal from the main hire companies. Most of the time you get a better rate than if you were to book direct.
holiday autos is another broker and they can sometimes be cheaper. It is always best to compare both companies.
When flying with Ryanair, Hertz car rentals offer a good deal. You should always use the Hertz link on the Ryanair web-site for a better rate.