Mexicans worried about highway security are increasingly skipping long road trips in favor of flying while their vehicles are delivered on giant car-carriers known as godmothers.

The fear of holdups, kidnapping or driving into a shootout between gangs of heavily armed traffickers is a by-product of the country's crackdown on drug cartels, which has killed more than 47,500 people in just over five years.

As a result, the use of trucks that carry about a dozen cars protected by satellite tracking beacons and full insurance coverage, has increased by between 20 percent to 60 percent since 2008, depending on the region, and operators say much of the new business is from Mexicans too scared to drive.

Until a few years ago, the service was almost exclusively used by companies dedicated to the sale of new and used cars, said Elizabeth Velazquez, who owns a business providing the vehicle-carriers in Tijuana, on the U.S. border.

People who would normally have driven themselves long distances in the past would now often rather pay someone to deliver their vehicle while they take a plane.

Now they won't risk it, because many of them get attacked or kidnapped along with their families, Velazquez said.

Some of the more common carrier routes are from Tijuana and other cities along the U.S. border, where violence is worse, to southern Mexican cities.

Robberies on highways increased by almost a third in 2010 compared with 2009, according to government figures, and more than 80 percent of robberies on Mexico's roads in the last three years involved violence.

The cost of the godmothers service starts at between 6,000 to 9,000 pesos (about $460 (293.78 pounds) to $690) per trip for a typical sedan, depending on the model and distance involved. Longer distances and fancier cars would add to the cost.

Velazquez estimates that the number of orders from individuals, mostly people moving house who want their car taken to their new home, shot up by 30 percent between 2010 and 2011.

For example, a gentleman wanted us to move his pickup truck to Jalisco (state) because in December 2010 he was kidnapped and assaulted. Afterwards he didn't want to risk travelling alone. There are a lot of cases like that, she said.

If the police, the army, whoever, can't do anything for your security, it's better you pay.

The situation is so bad in some areas that companies offering a godmother service will not deliver vehicles after 6 p.m., said one driver of the carriers who gave his name only as Juan Pablo.

He highlighted the town of Fresnillo in Zacatecas, a central mining state that has become a hotspot for violence as members of the Zetas drugs gang fight rivals for smuggling routes.

If you arrive after 6 p.m. you know that you will be at risk. It is better for you to stay at a hotel and tell the client to wait until the following day, the driver said.

They get angry because we are supposed to make deliveries within five to 10 days, but you can't do anything, he said.

In seven years as a driver I've not seen anything like it.

(Writing by Daniel Wallis; Editing by Doina Chiacu)